IRLF 


3Dfi 


GIFT   OF 


The  Engineer 
in  Field  and  Office 


New  Ideas  for  Securing  Uncom- 
monly Quick,  Accurate  and 
Economical  Results.  Reprinted 
from  the  Engineering  News-Record. 


ENGINEERING  NEWS-RECORD 

Tenth  Avenue  at  Thirty -Sixth  Street 

New  York 

1918 


Copyright  1918 
McGraw-Hill  Publishing  Co.,  Inc. 


PREFACE 

Civil  Engineering  is  an  art  of  which  it  can  never  be  said  that 
it  "stands  still."  It  keeps  pace  with  human  needs — and  human 
necessities  are  ever  expanding. 

Every  year — every  month — almost  every  week — witnesses  fresh 
demands  for  more  conveniences,  quicker  transportation,  more  effec- 
tive safeguards  for  public  health  and  comfort. 

In  meeting  these  demands,  civil  engineers  are,  happily,  most 
efficient.  The  profession  is  continually  making  new  discoveries — 
putting  forth  new  inventions — suggesting  new  applications  of 
former  theories — devising  more  effective  designs — improving  upon 
the  old  methods. 

Recognizing  its  obligations  to  the  field  it  serves,  the  Enginering 
News-Record  not  only  opens  its  columns  freely  to  the  authors  and 
originators  of  these  new  ideas  so  that  their  experiences  may  be 
passed  along  for  the  benefit  of  others,  but  is  continually  seeking  out 
the  new  and  helpful. 

These  advances  thus  become  incorporated  into  the  common  prac- 
tice long  before  they  get  into  the  books  or  become  part  of  the 
teachings  of  the  schools. 

The  best  of  the  new  ideas  which  have  recently  appeared  in  the 
News-Record  have  been  collected  for  this  volume. 

The  editors  feel  that  many  of  them  are  too  valuable  to  remain 
hidden  in  the  files  of  a  periodical,  even  of  a  journal  whose  back 
numbers  are  so  frequently  consulted  as  are  those  of  the  Engineering 
News-Record. 

They  are  confident  that  in  this  accessible  and  permanent  form 
this  new  material  will  be  helpful  to  every  engineer  who  wishes  his 
work  to  be  abreast  of  the  times.  It  is  Civil  Engineering  brought 
up  to  date. 

For  the  most  part,  in  the  case  of  the  contributed  articles  we 
have  let  the  engineers  tell  their  own  story.  But  little  editorial 
responsibility  has  been  assumed,  beyond  the  elimination  of  occa- 
sional personal  and  local  references  in  the  articles  as  they  originally 
appeared  in  the  columns  of  the  Engineering  News-Record.  The  mere 
fact  that  they  were  admitted  to  these  columns  is  sufficient  guarantee 
of  their  good  faith  and  of  the  editors'  judgment  of  their  worth  as 
contributions  to  current  practice. 


380101 


CONTENTS 

I — Of  Value  to  the  Highway  Engineer 

II — Interesting  Lights  on  Building  Construction-Theory,  Design 
and  Methods 

III — Some  Capital  Things  in  Foundation  Work 
IV — New  Ideas  in  Designing  and  Building  Bridges  and  Dams 
V — Helps  for  Municipal  and  County  Engineers 

VI — Present-Day   Water-Works   Construction,   Maintenance,   Op- 
eration and  Repairs 

VII — Interesting  Solutions  of  Problems  in  Sewer  Construction 

VIII — What  Engineers  are  Doing  in  the  Fields  of  Flood  Control, 
Irrigation  and  Hydraulics 

IX — Practical  Pointers  for  Railway  Civil  Engineers 
X — Helpful  Suggestions  from  Recent  Concrete  Construction 
XI — Results  of  Recent  Tests  in  the  Laboratory 
XII — Practical  Hints  for  the  Surveyor 
XIII— Draftsmen's  Kinks 
XIV — Simple  and  Effective  Methods  for  Filing  Engineering  Data 


The  Engineer  in  Field  and  Office 
Of  Value  to  the  Highway  Engineer 

Traction    Is    a    Straight-Line   Function   of  Tire   Width 

It  has  been  recognized  for  many  years  that  the  narrow  steel  tire 
is  enormously  destructive  to  earth  and  gravel  roads.  The  formation 
of  a  rut  begins  practically  with  the  passage  of  the  first  vehicle 
improperly  equipped.  The  U.  S.  Department  of  Agriculture  has 
shown  that  the  effort  necessary  to  draw  a  certain  load  is  an  inverse 


^ 

** 

*** 

^ 

** 

^ 

^ 

^ 

^ 

^ 

^ 

x 

<^ 

' 

200          300           400           SOO           600           700           800           SOL 

RDunds  \\feight   (Gross  Load) 
Per  lineal  inch  width  oFftre. 

Graph  Shows  Uniformity  of  Test  Conditions 

function  of  the  tire  width,  and  in  this  manner  forwards  another 
argument  against  excessive  load  concentrations  on  the  road  surface. 
The  accompanying  curve  is  plotted  from  data  obtained  under 
similar  conditions  of  moisture  and  atmosphere.  The  earth  road  was 
plowed,  graded  and  rolled  between  each  series  of  tests,  and  its 
condition  throughout  the  investigation  was  probably  as  uniform  as 
the  nature  of  the  test  warranted.  A  gross  wagon  load  of  5000 
Ib.  was  maintained,  the  tire  width  being  varied  from  U  in.  to 
6  in. 


The  Engineer  in  Field  and  Office 


The  unit  draft  decreases  directly  as  the  weight  per  inch  width 
of  tire  decreases,  until  a  weight  of  250  Ib.  per  inch  of  tire  is 
reached,  as  is  indicated  by  the  curve.  The  draft  for  a  6-in.  tire  is 
larger  than  that  for  a  5-in.  tire.  This  was  uniformly  true,  and 
indicates  that  there  is  not  only  nothing  gained  by  increasing  the 
width  beyond  a  certain  point,  but  there  may  be  a  positive  disad- 
vantage in  so  doing. 

Handling  Hot  Oil  on  Maintenance 
BY  H.  M.  LUKENS 

The  Los  Angeles  County  Highway  Department  has  a  unique 
system  of  heating  and  distributing  oil  in  the  maintenance  of  its 
paved  ways.  The  oil  is  too  cold  for  use  when  it  reaches  the  job  in 
trucks  from  the  main  depot.  It  is  poured  into  buckets  that  have 
previously  been  arranged  in  two  rows  with  another  row  on  top. 
A  portable  distillate  and  water  burner  has  proved  very  efficient. 
As  many  as  80  buckets  of  oil  can  be  heated  to  500°  F.  in  about  15 
min.  About  15  or  20  gal.  of  oil  at  this  temperature  is  placed  in 
the  hand  oiler  for  direct  application  to  the  patch  or  street. 

The  hand  oiler  is  made  of  sheet  iron,  with  a  boiler  about  2$ 
ft.  in  diameter  and  about  3i  ft.  high.  Inside  this  boiler  hangs  a 
cast-iron  pot  of  about  20  gal.  capacity,  the  intervening  space  between 
the  pot  and  the  boiler  being  used  as  a  firebox.  This  apparatus 
is  so  suspended  on  two  iron  wheels  that  the  center  of  gravity 
is  low  enough  to  keep  the  boiler  upright.  On  one  side  is  riveted 
an  iron  handle  with  which  to  move  it,  and  opposite  and  on  top 
of  the  boiler  is  the  hand  crank  for  the  oil  pump,  which  is  fastened 
to  the  bottom  of  the  oil  pot.  The  pump,  of  the  rotary  type, 
is  driven  by  sprocket  and  chain  from  the  hand  crank  and  is  capable 
of  developing  6  to  10  Ib.  pressure  per  square  inch.  To  the  pump 
is  attached  20  ft.  of  f-in.  metallic  hose  with  a  piece  of  f-in. 
pipe  3i  ft.  long  at  the  discharge  end.  This  end  is  plugged  so 
that  under  pressure  a  spray  is  formed  which  may  be  regulated  by  a 
throttle.  The  maximum  capacity  of  the  machine  is  about  125  gal. 
per  hour. 

It  has  been  found  from  experience  that  best  results  are  had 
from  heating  the  oil  to  the  desired  temperature  in  the  buckets  and 
using  it  in  the  hand  oiler  without  any  additional  fire  in  the  firebox. 
Fire  in  the  oiler  causes  the  bottom  of  the  oil  pot  to  cake  up,  which 
in  time  breaks  loose  and  clogs  the  pump. 


Highway  Engineering 


Concealed  Wood  Strips  for  Transverse  Joints 

Many  of  the  troubles  attending  the  use  of  transverse  joints 
in  concrete  pavements  can  be  avoided  by  installing  at  the  bottom 
of  the  slab  a  I -in.  wooden  strip  of  about  half  the  depth  of  the 
concrete.  In  this  manner  planes  of  weakness  where  transverse 
cracking  may  concentrate,  are  definitely  located. 

Four  joints  of  this  type  were  installed  in  1915,  and  withstood 
the  following  winter  without  cracking,  although  fine  hair  cracks 
appeared  in  June,  1916.  These  cracks  were  very  narrow  and 
followed  a  zigzag  line  around  the  individual  stones  of  the  concrete 
directly  over  the  wooden  strip.  The  zigzag  cracks  nowhere  departed 
more  than  2  in.  from  a  straight  line.  These  cracks  were  exposed 
to  traffic  all  summer,  and  no  spalling  of  any  kind  has  been  noticed. 

The  result  was  so  satisfactory  that  in  1916  10  consecutive  joints 
of  the  same  type  were  installed  on  each  of  two  roads.  These 
have  gone  through  one  winter  and  are  now  in  excellent  shape. 
Fine  hair  cracks  have  appeared  over  most  of  the  joints,  but  the 
fact  that  the  pavement  has  not  yet  cracked  over  a  few  indicates 
that  the  slabs  might  have  been  made  somewhat  longer  than  30 
ft.  in  this  particular  locality.  In  no  case  has  the  pavement  cracked, 
except  over  the  wooden  strips. 

The  advantages  obtained  by  this  method  over  other  types  of 
joints  are:  (1)  No  spalling  along  the  joints;  (2)  no  interference 
with  scr ceding  or  floating,  and  a  much  smoother  pavement;  (3) 
the  joints  are  cheaper  and  easier  to  install,  the  wood  may  be  of 
cheap  material  and  need  not  be  creosoted;  (4)  better  appearance  of 
the  road. 

The  advantages  of  this  method  over  nol  joints  at  all  are 
that  by  choosing  the  proper  length  of  slab  to  correspond  to  the 
width  of  pavement  and  to  climatic  conditions  the  cracks  will 
be  minimized  and  will  run  square  across  the  pavement  at  regular 
intervals  instead  of  occurring  haphazard  and  running  in  every 
direction. 

It  is  absolutely  necessary  that  the  top  of  the  joint  be  kept 
below  the  surface  of  the  slab  a  sufficient  distance  to  give  body 
enough  to  the  concrete  over  it  to  prevent  spalling.  This  minimum 
depth  has  not  yet  been  definitely  determined,  but  from  observations 
already  made,  a  distance  of  2i  in.  near  the  edges  and  3£  in.  near 
the  center  of  the  pavement  seems  to  work  out  very  well.  Should 
this  distance  be  much  greater,  it  probably  would  necessitate  decreas- 
ing the  length  of  the  slab  in  order  to  insure  the  cracking  at  the 
joints  only. 


The  Engineer  in  Field  and  Office 


A  simple  way  to  prevent  the  wooden  joints  floating  up  through 
the  concrete  is  to  drive  short  pegs  at  intervals  of  about  7  ft.  across 
the  road  and  nail  through  the  strip  into  the  pegs.  Bent  wires 
hooked  over  the  joint  would  answer  the  same  purpose.  The  strips 
should  be  installed  by  means  of  a  taper  installing  board  in  the 
usual  manner. 

Exact  Wear  of  Concrete  Pavements  Measured 

BY  A.  N.  JOHNSON 

Consulting    Highway    Engineer,    Portland    Cement    Association, 

Chicago 

The  usual  methods  that  have  been  devised  for  measuring  the 
wear  of  macadam  roads  are  open  to  considerable  error,  aside  from 
usually  being  rather  clumsy,  but  the  method  here  proposed  over- 
comes many  difficulties  and  is  also  extremely  simple  and  convenient. 
A  drill  hole  i  in.  in  diameter  is  made  in  the  pavement.  In  the  case 
of  a  concrete  pavement  it  may  be  2  or  2£  in.  in  depth.  In  the 


<-  ..........  -r  ..... 


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MachmeFvced  Steel 


-Flat  Sea  te 


6"-  ...........  * 

sFine  Thread 


Surface 
fofPare/Tjent 


efe- 


5  "%"Diarr>.  Copper  P/ug 
^CementGrout 

With  This  Device  Wear  of  Concrete  Can  Be  Easily  and 
Accurately  Measured 

bottom  of  the  drill  hole  is  set  a  copper  plug  about  I  in.  long,  with 
its  top  made  semi-spherical.  The  plug  is  embedded  in  the  hole 
with  cement  paste.  A  short  steel  scale  divided  into  inches  and 
hundreds,  small  enough  to  be  placed  in  the  drill  hole,  is  provided. 
At  its  end  is  a  small  button  with  conical  undersurface,  which  is 
to  rest  on  the  spherical  end  of  the  copper  plug.  The  hole  is  filled 
with  a  wood  plug,  left  flush  with  the  surface,  which  is  to  be 
removed  when  readings  are  to  be  made. 


Highway  Engineering 


A  convenient  method  of  measuring  is  to  have  a  U-shaped  handle, 
which  will  span  about  6  in.,  having  flat  ends  on  the  legs.  Drawn 
between  the  supports  is  a  tightly  stretched  thin  thread  or  wire 
1  in.  from  the  surface  of  the  pavement.  This  is  to  be  held  so 
that  the  thread  will  be  over  the  center  of  the  drill  hole.  The 
flat  ends  of  the  legs  rest  on  the  pavement  surface  and  the  measure- 
ments are  made  to  the  thread.  The  thread  may  first  be  placed 
longitudinally  with  respect  to  the  pavement,  then  transversely,  and 
in  as  many  other  positions  as  desired. 

Grasses  To  Protect  Road  Embankments 

BY  W.  C.  BUETOW 
Division  Engineer,  Wisconsin  Highway  Commission,  La  Force,  Wis. 

Much  damage  to  embankments  and  slopes  that  cannot  be 
prevented  even  by  the  provision  of  proper  drainage  and  keeping 
cattle  from  trampling  the  slopes  can  be  taken  care  of  by  the  planting 
of  well-chosen  grass,  which  should  be  properly  cared  for  until  a 
mat  or  blanket  has  formed. 

Grasses  do  not  form  a  mat  or  blanket  very  quickly,  due  to  the 
variance  of  the  climatic  conditions.  The  action  of  frost  is  the  most 
disturbing  factor,  and  on  account  of  the  depth  of  its  penetration 
the  upper  stratum  of  the  bank  is  kept  in  a  loosened  state  that  is 
very  susceptible  to  the  spring  rains. 

When  selecting  grasses  to  be  planted  on  the  slopes,  it  should  be 
kept  in  mind,  therefore,  that  a  grass  with  a  good  system  of  roots 
is  to  be  used,  as  well  as  one  able  to  withstand  the  hot  rays  of  the 
sun.  Grasses  that  will  grow  on  a  sunny  bank  probably  will  not 
take  root  and  form  a  mat  on  the  shaded  slopes,  in  which  case  a 
different  kind  of  grass  is  necessary. 

The  protection  to  the  bank  lies  almost  wholly  in  the  ability  of 
the  roots  to  interweave  so  minutely  as  to  form  a  system  to  reinforce 
the  surface  stratum.  Hungarian  brome  grass,  Canadian  blue  grass, 
fescue  grasses  and  Western  wheat  grass  are  good  to  plant.  In 
many  cases  sod  is  handy  to  get  and,  when  properly  cut  and  placed, 
offers  very  good  protection.  The  sods  must  be  held  in  place  by 
wooden  pegs  until  the  grass  has  taken  root. 

Seeding  and  planting  are  equally  successful  when  conducted 
properly.  The  surface  in  each  case  must  be  prepared  in  order  to 
make  it  at  all  conducive  to  a  good  growth.  The  seed  cannot  be 
merely  distributed  on  the  slope  and  left  with  the  hope  that  it  will 
catch.  If  necessary,  the  ground  should  be  manured  before  any 
seeding  is  done  and  if  a  sandy  slope  is  treated,  the  surface  must  be 


The  Engineer  in  Field  and  Office 


protected  from  the  wind  with  straw  or  brush  until  the  grasses 
are  able  to  withstand  the  elements. 

Different  kinds  of  soil  require  a  certain  kind  of  grass  or  a 
combination  of  several  kinds.  For  shaded  places  a  combination  of 
Kentucky  blue  grass,  wood  meadow  grass,  crested  dog's  tail  and 
various  leaved  fescues  are  well  adapted. 

Clay  soils  can  be  treated  with  a  mixture  of  Kentucky  blue  grass, 
English  rye  and  fancy  red  top.  The  rye  grass  gives  an  early  quick 
result,  the  red  top  makes  a  bottom  grass,  and  the  blue  grass  is 
the  permanent  feature. 

Sandy  soils  require  a  quickly  growing  binding  grass  that  will 
withstand  the  drought.  Creeping  bent,  Rhode  Island  bent  and 
fine-leaved  fescue  are  grasses  that  answer  this  purpose.  Western 
wheat  grass  has  unusual  ability  to  grow  on  the  sunny  side  of  an 
embankment.  Creeping  bent,  Canada  and  Kentucky  blue  grass  and 
crested  dog's  tail  are  quick  growing,  deep-rooting  grasses  that  will 
bind  the  soil  until  such  time  as  the  more  permanent  grasses  are  in 
possession.  Sweet  clover  and  creeping  honeysuckle  are  recommended 
for  planting  in  cuts. 

Dump  Road  Drags  Before  Pulling  Across 
Railroad  Crossings 

Men  operating  road  drags  should  dump  their  drags  or  unhook 
one  end  of  the  drag  chain  and  pull  the  drag  endwise  whenever  a 
railroad  crossing  must  be  crossed,  according  to  the  "Bulletin"  of 
the  Iowa  State  Highway  Commission.  Railroad  men  are  complaining 
that  this  precaution  is  not  being  taken.  They  have  appealed  to  the 
commission  to  do  all  in  its  power  to  get  dragmen  to  watch  this  point. 
Pulling  the  drag  across  the  tracks  in  the  usual  manner  leaves  the 
space  between  the  rails  and  the  planking  on  each  side  filled  with 
dirt  and  small  stones.  Each  passing  train  packs  this  material  down, 
and  the  next  dragging  fills  the  space  again.  This  continues  with 
every  dragging ;  and  if  a  good-sized  hard  hand-stone  becomes  packed 
in  this  space,  there  is  the  best  possible  situation  developed  for  a 
derailment.  Derailments  of  hand  cars  and  motor  cars  are  of  almost 
daily  occurrence  because  they  are  not  heavy  enough  to  crush  the 
dirt  and  stone  sufficiently  to  allow  the  wheels  to  retain  a  safe  hold 
on  the  rails.  There  have  been  many  derailments  of  trains  traceable 
to  this  cause,  but  so  far,  no  serious  wrecks. 


Highway  Engineering 


A  New  Subgrader  Design 

Instead  of  the  usual  scraper  blade  at  right  angles  to  the  center 
line  of  the  road,  a  new  subgrader  used  in  California  has  four  pairs 
of  plow-shaped  blades  arranged  to  balance  the  thrust.  These  are 
set  at  an  angle  with  the  center  line,  and  as  a  result  the  tendency 
to  pile  up  earth  ahead  of  the  grader  is  avoided.  This  feature  makes 
possible  more  work  of  a  satisfactory  character  with  fewer  laborers 
than  is  obtainable  from  the  ordinary  type  of  subgrader. 

A  feature  of  the  new  device  is  the  quadrant  and  lever  regulation 
of  the  blade,  whereby  the  height  of  the  blade  can  be  adjusted 
without  the  use  of  special  tools.  This  arrangement  also  permits 
raising  the  blades  until  the  scraper  rests  on  a  central  circular 
plate,  or  turntable,  in  which  position  it  can  be  easily  swung  parallel 
to  the  center  line  of  the  road  to  allow  space  for  passing  vehicles, 
or  so  that  it  may  be  trundled  off  the  graded  roadbed.  Angle  irons 
are  provided  as  guides  to  keep  the  wheels  on  the  header. 

Since  the  blades  shear  through  the  material  rather  than  pile  it 
up  ahead,  depressions  in  the  subgrade  are  avoided  to  a  great  extent. 
The  grade  may  be  controlled  to  a  nicety  on  account  of  the  clean 
action  of  the  plow  blade,  and  thus  a  considerable  saving  in  concrete 
is  effected.  It  is  notable  that  the  setting  of  the  blade  at  acute 
angles  has  reduced  the  tractive  effort  below  that  required  by  the 
ordinary  grader.  The  most  effective  work  has  been  done  when  the 
grader  is  hauled  by  cables  running  from  its  extreme  ends  to  the 
tractor,  which  is  kept  about  30  ft.  in  advance. 

Earth-Road  Maintenance  bys  Contract 

BY  C.  S.  BENNETT 
State  Engineer  and  Inspector,  Greenup,  Ky. 

After  considering  various  methods  of  maintenance  for  the  new 
roads  of  Greenup  County,  Ky.,  it  was  decided  to  adopt  the  contract 
method.  The  specifications  as  finally  drawn  up  embody  provisions 
for  dragging,  cleaning  ditches  and  culverts,  cutting  weeds  on  the 
county's  right-of-way,  maintaining  a  crown,  etc.  Bids  were  then 
asked  for  and  work  on  each  section  was  let  to  the  lowest  responsible 
bidder.  Mileage  was  considered  the  basis  for  payment,  while  slides 
and  washouts  were  paid  for  by  the  cubic  yard.  The  work  was 
usually  let  in  five-mile  sections. 

A  road  drag,  two  drag  scrapers,  one  wheel  scraper,  shovels,  and 
mattocks,  were  furnished  to  each  contractor,  being  charged  against 
him  with  the  provision  that  at  the  expiration  of  his  contract  he 
account  for  all  tools  supplied  to  him.  In  addition,  two  large  blade 


8  The  Engineer  in  Field  and  Office 

road  graders  were  purchased  by  the  county,  being  lent  to  the  various 
contractors  as  they  were  needed  in  shaping  up  the  roads  in  the 
spring  season.  A  contractor  was  required  to  own  at  least  one  team. 

The  work  was  under  the  supervision  of  the  county  road  engineer, 
who  notified  the  contractors  when  they  were  to  drag  the  roads  and 
when  to  cut  the  weeds  on  the  county's  right-of-way.  He  also  issued 
to  them  instructions  as  to  other  details  of  the  work. 

Payments  were  made  quarterly,  the  payments  being  so  distributed 
as  to  make  a  maximum  payment  fall  at  a  time  when  the  greatest 
amount  of  maintenance  was  necessary.  Thus,  for  instance,  a 
contract  dated  Jan.  1,  1916,  stated  that  payments  would  be  made  to 
the  contractors  as  follows:  20%  Apr.  1;  40%  July  1;  15%  Sept.  1 
and  25%  Dec.  31.  The  maximum  payment,  40%,  was  made  at  the 
end  of  the  spring  season,  during  which  time  the  greatest  amount 
of  work  is  necessary  to  keep  the  roads  in  condition.  In  addition, 
each  contractor  was  required  to  give  bond  for  the  faithful  perform- 
ance of  the  work  called  for  in  his  contract.  Strict  adherence  to  the 
terms  of  the  contract,  especially  in  regard  to  dragging  the  roads, 
was  insisted  upon. 

The  cost  of  maintenance  on  seven  sections  of  road  for  the  year 
1916  is  as  follows: 

Length, 
Contract  No.  Miles 

45  Dl  4 

45  C  1  5 

45  Gl  5 

45  G  2  5 

45  E  1  3 

45  A  1  5 

45  G  3  3 

From  a  comparison  made  with  similar  work  done  in  other 
counties  under  various  other  methods,  the  writer  is  led  to  believe 
that  the  contract  method,  properly  looked  after,  is  the  cheapest 
method  of  continuous  maintenance  for  earth  roads. 

Peaked  Subgrade  Provides  Better  Underdrainage 

A  concrete  or  brick  slab  laid  with  a  flat  bottom  upon  a  flat 
subgrade  affords  no  possibility  for  underdrainage.  As  a  result, 
seepage  through  the  pavement  at  various  points — such  as  expansion 
joints,  along  car  rails,  and  through  semiporous  spots — keeps  the 
subgrade  moist  and  affords  a  good  chance  for  frost  upheavals  with 
the  resultant  cracking  of  the  rigid  surface.  While  there  is  but 
slight  importance  attached  to  such  seepage  if  the  construction  is 
on  a  sandy  or  porous  soil,  a  clay  or  heavy  soil  brings  about  conditions 
which  cannot  be  disregarded. 


Bid  per 

Bid  per 

Bid  per 

Total  Cost 

Milerper 
Maintenance 

Cubic  Yard 
for  Earth 

Cubic  Yard 
for  Rock 

Mife 

$45.00 

0.35 

0.40 

$48.50 

56.00 

0.37 

0.37 

61.05 

40.00 

0,24 

0.35 

40.35 

60.00 

0.30 

0.30 

76.22 

53.00 

0.35 

0.40 

53.00 

100.00 

0.20 

0.50 

138.00 

75.00 

0.35 

0.60 

75.00 

Highway  Engineering 


9 


The  ordinary  precaution  of  laying  a  slab  with  a  crowned  bottom 
upon  a  crowned  subgrade  does  not  entirely  alleviate  these  conditions, 
as  the  slab  is  laid  directly  upon  the  heavy  soil,  filling  every  crevice 
and  blocking  a  free  movement  of  the  water  from  under  the  crust. 


^  * 


on  each  Side  offibacf 
c*ndfill.edwt+h  crushed 
Stone  or  Grave/ 

Shpe  of -Side  Drains  %'per-fl; 

Peaked  Subgrade  Brought  Level  with  Sand  or  Gravel 
Affords  Best  Possible  Drainage 

The  newer  specifications,  which  require  2  or  3  in.  of  sand  to  be  laid 
upon  the  flat  subgrade,  and  upon  this  sand  bed  to  lay  a  flat-bottomed 
slab,  are  undoubtedly  an  improvement,  but  it  is  questionable  whether 
this  method  will  prove  to  be  entirely  sufficient. 

The  subgrade  should  not  be  crowned,  but  peaked,  as  indicated 
in  the  illustration.  On  this  a  sand  covering  about  2  or  3  in.  in 
thickness  at  the  center  can  be  well  rolled  to  a  flat  surface.  This  will 
allow  a  free  movement  of  the  water  between  the  bottom  of  the  slab 
and  the  top  of  the  impervious  subgrade  and  should  afford  adequate 
protection  against  the  troubles  outlined  in  the  foregoing. 

Oiled  Shoulders  Resist  Erosion 

A  mountain  road  in  San  Bernardino  County,  Calif.,  with  a 
maximum  grade  of  5%  presented  a  serious  problem  in  the  protection 


(TANQGNTS) 


(ctmvtof 

Oiled  Road  Shoulders,  San  Bernardino  County,  California 

of  high  embankments  from  the  wash  of  storm  water  running  off 
the  paved  surface.    The  problem  would  have  been  simple  if  funds 


10  The  Engineer  in  Field  and  Office 

had  been  available  for  concrete  curbs  and  gutters.  Instead,  the 
following  plan,  illustrated  in  the  accompanying  cross-sections,  was 
adopted:  The  shoulders  for  2  ft.  in  width  were  raised  from  6  to  8 
in.  by  filling  with  the  adjacent  gravelly  soil,  and  were  rounded  off 
to  easy  curves.  The  shoulders  were  then  given  two  coats  of  75% 
asphaltic  oil,  each  coat  being  properly  sanded.  Cutouts  for  the  water 
were  provided  at  safely  placed  points  and  at  culverts.  This  method 
of  construction  formed  an  earth  curb,  and  the  pavement  acted  as 
the  gutter.  The  oiled  shoulders  have  a  sufficiently  hard  surface 
to  resist  erosion  and  also  serve  to  protect  the  edge  of  the  macadam 
from  breaking  down  under  wheel  traffic.  There  was  a  considerable 
saving  over  standard  practice,  the  cost  being  only  about  2£c.  per 
lin.ft.  of  shoulder. — J.  S.  Bright,  Jr.,  Engineer,  San  Bernardino 
County  Highway  Commission,  San  Bernardino,  Calif. 

Curb  with  Integral  Expansion  Joints 

BY  E.  E.  KIRKPATRICK 
City  Engineer,  Bartlesville,  Okla. 

Better  quality  of  work,  better  and  more  positive  expansion 
joints,  less  risk  in  construction,  better  protection  against  drying, 
elimination  of  the  danger  of  mortar  scaling,  elimination  of  the  dam- 
age caused  by  removing  templets  and  forms  while  the  work  is 
green,  and  a  better  top  facing  owing  to  the  fact  that  it  is  placed 


immediately  after  the  body  concrete  has  been  deposited,  are  the 
advantages  derived  from  the  new  specification  for  concrete  curbs 
recently  adopted  by  Bartlesville,  Oklahoma.  The  curb,  of  the  di- 
mensions shown  in  the  illustration,  is  blocked  off  into  sections  not 
exceeding  7  ft.  in  length  by  transverse  expansion  strips  not  less 
than  -fa  in.  nor  more  than  T%  in.  in  thickness.  These  strips,  placed 
before  the  concrete  is  deposited,  are  composed  of  asphalt-roofing 
sheets,  asphaltic  felt  or  other  elastic  asphaltic  material  cut  to  the 
form  of  the  cross  section  of  the  curb. 


Highway  Engineering 


11 


The  concrete  is  spaded  thoroughly,  the  expansion  strips  being 
held  in  place  by  thin  boards  or  metal  strips  that  are  raised  as  the 
concreting  progresses.  The  mortar  top  dressing  is  placed  as  soon 
as  the  form  is  filled.  Dressed  lumber  is  used  for  forms,  and  the 
concrete  is  mixed  to  such  consistency  that  with  proper  spading  a 
perfect  face  is  obtained. 

Save  Trouble  by  Using  Well-Built  Forms 

As  the  engineer  watches  the  ordinary  contractor  set  his  side 
forms  for  concrete  roadwork,  he  easily  realizes  that  not  enough 
consideration  is  given  to  their  construction  and  grade  layout — facts 


—  _ 

*"->.g£xf'     I       &= 


<~6«>\  wood  Form 
notched  crs 


FI0.4 

Stands  Much  Rough  Handling 

which  later  on  are  sure  to  cause  much  extra  trouble  and  loss  of 
time.  The  forms  should  not  of  course  be  built  to  a  degree  of  over- 
nicety,  but  should  be  so  constructed  as  to  prevent  their  becoming 


12  The  Engineer  in  Field  and  Office 

easily  bent,  warped  or  worn  out  of  shape.  Another  feature  often- 
times overlooked  is  the  desirability  of  staggering  the  joints,  thus 
preventing  an  undulation  forming  across  the  road  in  case  the 
joints  are  out  of  grade.  To  obtain  a  method  of  easily  supporting 
side  forms  for  grade,  2  x  2-in.  wooden  stakes  are  driven  to  the 
proper  elevation  of  the  bottom  of  the  form;  and  they,  in  conjunc- 
tion with  alignment  stakes  which  are  not  shown,  and  together  with 
the  method  of  staggering  the  joints,  make  a  satisfactory  arrange- 
ment. Figs.  2  and  3  show  details  of  wooden  side-form  construction, 
Fig.  2  showing  the  angle  iron  extending  6  in.  beyond  the  end  to 
insure  that  adjacent  forms  will  be  maintained  at  the  same  elevation. 
Fig.  3  shows  a  modified  design  that  prevents  the  angle  iron  from 
becoming  easily  bent  when  the  forms  are  roughly  handled,  while 
Fig.  4  shows  a  side  form  made  entirely  of  wood. 

Drainage  Where  Highway  Parallels  Railroad 

BY  C.  S.  BENNETT 
Highway  Engineer,  Greenup  County,  Kentucky 

In  constructing  a  section  of  a  state-aid  road  in  Greenup  County, 
Kentucky,  the  highway  paralleled  the  railroad  for  a  distance  of 
one-half  mile.  The  railroad  fill  is  8  ft.  higher  than  the  road  surface 


gpS^Wpsp 


WTwvmgi 

'^TWvv.-t  •<-.•*•• 


VillllllllllllllHIIIIIIIIIIIIIIHIMIIMMllUMIIIIllllllllilinHllliliiiiiiiinnilMllliilHHIII'HIIIinilllfJIIIiilljilllllllllll/llllMII 

\  Culver  i  Pipe  \ 

^llillllilllilliiilllilllllliiniiiiNhiiNMnl'nilllliiiiniiiiliHIiluviiiii.iiiiiiiiiMiiiiiiiiiiiiiiijiiiiiiiiuaiiiiiniiiiiiiiiiiiMMiiiiniii) 


Drop  Inlet  Takes  Care  of  Drainage  Where  Railroad 
Parallels  Highway 

for  about  half  of  this  distance.  As  all  culverts  extended  through 
both  fills,  it  was  decided  to  adopt  the  inlet  method  used  on  paved 
roads  and  streets.  Excavations  were  made  in  the  ditch  line  over 
the  existing  pipe  culverts,  all  of  which  were  48  in.  in  diameter 
and  of  corrugated  iron,  and  a  section  was  sawed  out  of  the  top  of 


Highway  Engineering 


13 


the  pipe.  Short  sections  of  12-in.  corrugated  culvert  pipe  were 
then  placed  on  end,  and  fastened  to  the  large  pipe  by  means  of  an 
easily  made  metal  collar  through  which  several  bolts  were  run.  The 
top  of  the  riser  pipe  was  provided  with  a  concrete  apron  6  in.  thick, 
the  width  of  the  bottom  of  the  ditch,  and  extending  about  3  ft. 
along  the  ditch.  A  few  small  reinforcing  bars  were  inserted  in 
the  green  concrete,  and  formed  an  effective  grating  which  excluded 
foreign  materials. 

Unusual  Road  Drainage 

Lincoln  Highway,  east  from  Wooster,  Ohio,  at  this  point  dips 
from  a  comparatively  level  stretch  to  a  grade  of  some  6  to  8%. 
Across  the  ridge  where  the  road  begins  to  dip  is  an  intersecting  road 
at  right  angles.  At  this  point  there  was  a  culvert  pipe  on  both 


Unusual  Drainage,  Lincoln  Highway,  Ohio 

sides,  while  open  ditches  were  provided  for  drainage  of  the  side 
hill  and  to  carry  considerable  accumulated  water  from  the  more 
level  place  above. 


14 


The  Engineer  in  Field  and  Office 


To  avoid  scouring  on  the  deep  side  ditches  on  the  improved 
road,  about  300  ft.  of  30-in.  corrugated-iron  culvert  pipe  extending 
from  the  crest  of  the  hill  to  a  creek  at  the  foot  of  the  hill  has  been 
installed.  Apparently  it  is  not  intended  to  be  covered.  Drainage 
water  from  the  level  stretch  on  the  opposite  side  of  the  road  passes 
through  a  culvert  pipe  at  the  crest  and  then  is  conducted  diagonally 
across  the  roadbed  into  the  large  culvert  pipe  by  a  segmental  cast- 
iron  culvert  pipe. 

Stone  Header  Prevents  Failures  in  Paving 

Baltimore,  Md.,  has  adopted  a  detail  of  pavement  construction 
to  prevent  failures  at  such  points  where  a  hard  paving  material 
like  granite  block,  brick  or  wood  block  adjoins  a  softer  material 
like  asphalt.  This  detail  is  as  follows :  A  well-jointed  stone  header, 
12  in.  or  more  in  depth  and  4  or  5  in.  in  width,  is  constructed  across 


^.-Wearing  Surface 


... — vitrified     Block 


Sunken  Stone  Header  Prevents  Failures  in  Paving 

the  street  parallel  to  and  14  in.  below  the  finished  surface.  The 
concrete  base  is  placed  on  one  side  of  the  header  for  the  block 
pavement,  and  on  the  other  side  for  the  asphalt  pavement.  The 
blocks  are  laid  tight  against  the  header,  which  in  case  of  a  3i-in. 
vitrified  block  gives  a  2-in.  bearing.  When  the  asphalt  is  laid,  the 
binder  course  is  brought  flush  with  the  header;  and  the  topping  or 
wearing  surface  is  laid  over  the  header  to  the  finished  contour  of 
the  street,  thus  leaving  the  header  14  in.  below  and  entirely  hidden 
from  view. 

Road  Surface  Affects  Tractive  Effort 

A  series  of  tests  has  just  been  completed  in  California  which 
was  planned  to  determine  the  tractive  effort  required  to  move 
vehicles  over  various  types  of  roads.  Tests  of  a  similar  character 


Highway  Engineering 


15 


which  were  previously  made,  notably  by  the  U.  S.  Office  of  Public 
Roads  and  Rural  Engineering,  afforded  no  data  suited  to  California 
conditions  or  which  could  be  used  as  the  starting  point  for  the 
further  series  of  tests  in  tire  wear  and  gasoline  consumption  which 
is  contemplated. 


100- 

o- 


TEST  NO.  50,  CONCRETE 


83lb. 


TESTN0.46.  OIL  MACADAM  REVERSE  (DOWN  GRADE) 


Dynamometer  Curves  Vary  Much 

In  planning  the  tests,  it  was  decided  to  concentrate  effort  on 
securing  constant  conditions  for  a  short  length  of  time  during  which 
measurements  could  be  made,  rather  than  to  make  long  runs  and 
average  the  results.  This  policy  was  considered  the  best  where 
experiments  were  to  be  made  on  the  open  highways  and  on  several 
types  of  roads.  One  vehicle  was  therefore  equipped  and  moved  at 
the  same  speed  over  the  various  road  surfaces  to  be  compared.  For 
this  service  a  standard  farm  wagon  was  selected,  equipped  with 
steel  axles  of  equal  length  and  38-  and  46-in.  wheels  in  front  and 
rear,  respectively,  all  wheels  having  4-in.  tires.  The  gross  load 
was  3  tons,  consisting  of  rice  in  sacks.  The  speed  was  kept  very 
close  to  2.4  miles  per  hour,  and  tests  were  run  on  level  grades  or, 


16  The  Engineer  in  Field  and  Office 

where  slight  grades  were  unavoidable,  test  runs  were  made  in 
both  directions  and  results  averaged.  At  the  time  of  the  tests  the 
usual  sunny  summer  weather  obtained,  with  maximum  temperature 
of  105°. 

The  tractive  effort  was  measured  by  a  small  dynamometer 
attached  to  the  tongue  of  the  wagon,  which  recorded  the  momentary 
pull  at  all  times  during  the  test  runs  and  the  total  pull  for  the 
test  period.  The  measurement  of  distance  is  accomplished  by 
unwinding  a  cord  of  definite  length  from  a  drum  within  the  device. 
In  a  50-ft.  run  an  error  of  6  in.  in  cord  length,  due  to  stretching 
or  any  other  cause,  would  introduce  an  error  of  only  1%  in  the 
result. 

The  record  of  tractive  effort  is  made  by  the  pencil  actuated  by 
a  lever  attached  to  the  strong  spring  compressed  by  the  pull.  The 
integrating  device  operates  on  the  planimeter  principle,  but  as  the 
measuring  wheel  makes  one  revolution  for  each  4  in.  and  can  be 
read  to  one-thousandth  of  a  revolution,  the  instrument  is  10  to  20 
times  as  sensitive  as  the  ordinary  planimeter. 

RESULTS  FAVOR  UNSURFACED  CONCRETE 

As  shown  by  the  accompanying  table  and  curves,  the  resistance 
encountered  on  oiled  surfaces  was  considerably  more  than  on 

TYPICAL,    RESULTS   FOB   VARIOUS    SURFACES 

Tract.  Resist. 

Test  No.  Kind  of  Road  Condition  of  Road  Location  Total  Per  Ton 

29-30-31     Concrete 

(unsurfaced) .  .    Smooth,  excellent    Near  Davis 83.0       27.6 

*  11-1 2         Concrete 

(unsurfaced) .  .    Smooth,  excellent    Near  Davis 90.0       30.0 

26-27-28  Concrete  (%-in. 
surface  as 
phaltic  oil  and 

screenings)     ...    Smooth,  excellent    Near  Davis 147.6       49.2 

13-14  Concrete      (  %  -in. 

surface      as- 
phaltic    oil    and 

screenings)    ...    Smooth,  excellent    Near  Davis 155.0       51.6 

9-10  Macadam 

(water-bound).    Smooth,   excellent    Near  Davis 193.0       64.3 

22-23  Topeka  on  con- 
crete)   Smooth,  excellent Near  Davis 205.5  68.5 

Gravel      Compact,    good   condition..     Near  Davis 225.0        75.0 

t45-48          Oil  macadam  ...    Good,    new Near   Sacramento  234.5        78.2 

J46— 47          Oil  macadam  ..  .    Good,    new    Near   Sacramento  244,0        81.3 

33  Gravel     Packed,  in  good  condition.  .    Near  Davis 247.0        82.3 

18-19-20     Topeka  on  plank  Good  condition,  soft,  wagon 

left  marks On        Causeway 

near  Davis    .  .  265.0  88.3 

34  Earth  road    ....    Firm,  1%-in.  fine  loose  dust  Near  Davis 276.0  92.0 

24-25            Topeka  on  plank  Good  condition,  but  soft.  .  .    Near  Davis 278.0  92.6 

1-2-5            Earth  road Dust    %    to  2  in Near  Davis 298.0  99.3 

3-4                 Earth    Mud,  stiff,  firm  underneath.    Near  Davis 654.0  218.0 

6-7                Gravel     Loose,   not  packed Near  Davis 789.0  263.0 

*  Graphic  record  indicates  that  the  load  was  being  accelerated  when  test  was  started, 
t  Drawn  with  motor  truck  at  2%  miles  per  hour.  J  Drawn  with  motor  truck  at  5 
miles  per  hour. 

concrete.    It  was  pointed  out  that  this  difference  would  be  less  at 


Highway  Engineering 


17 


lower  temperature,  but  the  tests  were  made  under  normal  conditions 
in  the  central  California  valleys. 


Curves  for  Tests  Nos.  2,  3  and  7 

The  supervision  of  the  tests  has  been  in  the  hands  of  Prof.  J.  B. 
Davidson,  of  the  University  of  California,  who  is  the  inventor  of 
the  dynamometer. 

Side-Hill  Fill  Held  by  Trees 

In  the  construction  of  one  of  the  roads  in  the  northern  part 
of  New  York  State  the  side-hill  fill  has  to  be  made  over  a  wooded 
area.  The  usual  procedure  in  such  cases  is  to  cut  off  the  timber, 
leaving  the  ground  clear  before  beginning  to  make  the  fill.  In 
this  case  it  has  been  decided  to  leave  the  trees  standing  on  the 
supposition  that  by  so  doing  the  fill  will  be  less  apt  to  slip.  The 
only  clearing  of  trees  which  will  be  allowed  will  be  in  the  space 
included  between  shoulder  lines. 


18 


The  Engineer  in  Field  and  Office 


Pavement  Along  Rails  Should  Be  Lowered 
BY  E.  W.  WENDELL 

Assistant  Engineer,  New  York  State  Highway 
Department,  Albany 

All  pavements,  within  the  line  of  possible 
contact,  should  be  laid  below  the  plane  of  the 
tread  of  a  car  wheel.  Consider  the  case  of  a  T- 
rail  such  as  is  shown  in  the  illustration — though 
it  should  be  borne  in  mind  that  the  above  rule 
holds  for  any  other  type  of  rail.  The  rail  head  is 
2i  in.  wide,  while  the  wheel  tread  is  3  in.,  meas- 
ured from  the  gage  line.  Hence,  even  without 
any  wear  in  the  tread,  if  the  pavement  is  flush 
with  the  rail  top  the  tread  will  ride  in  contact 
with  the  paving  surface  for  the  width  of  the 
overhang.  But  the  rail  head  wears,  and  not  in- 
frequently the  tread  grooves,  so  that  the  over- 
hang is  below  the  head  on  tangent  track.  While 
perhaps  the  railway  company  should  be  pro- 
hibited from  using  such  equipment,  it  must  be 
recognized  that  such  cars  are  owned  and  oper- 
ated; and  as  long  as  an  adverse  condition  exists, 
engineers  should  meet  it  with  proper  design. 

The  speed  of  cars  being  generally  regulated 
by  law  to  a  certain  safe  maximum,  there  is  no 
necessity  for  elevating  the  outer  rail  on  curves 
to  an  amount  that  will  distort  the  cross-section 
of  the  street  and  spoil  the  section.  The  illus- 
tration shows  a  2-in.  elevation,  but  this  is  more 
than  will  be  found  in  practice  except  in  very 
unusual  cases.  This  section  shows  clearly  the 
details  and  dimensions  used  to  overcome  the 
destructive  effect  of  the  overhanging  tread,  but 
even  on  tangents  at  least  a  Hn.  difference  in 
grade  should  be  maintained  between  the  rail  head 
and  the  pavement  surface  directly  adjacent  to  it. 
On  curves  the  amount  of  superelevation  must 
first  be  decided  upon,  as  from  this  is  determined 
the  difference  in  elevation  between  the  rail  head 
and  the  pavement  surface  on  the  inside  of  the 
curve. 


Building  Construction  19 

The  following  are  good  rules  to  follow  in  determining  these 
points:  (1)  Place  the  outside  rail  (D  in  the  section)  at  the  eleva- 
tion it  would  have  were  the  track  on  a  tangent;  (2)  in  the  case 
of  double  tracks,  give  B  the  same  elevation  as  D,  if  there  is  not 
much  longitudinal  grade  at  the  curve.  This  plan  leaves  the  half  of 
the  street  on  the  outside  of  the  curve  with  its  normal  crown, 
and  gives  the  other  half  a  proper  slope  toward  the  gutter.  If 
there  is  much  grade,  an  inlet  may  be  located  before  the  curve 
is  reached,  to  catch  the  gutter  drainage,  so  that  D  can  be  placed 
even  with,  if  not  below,  the  gutter  grade;  and  B  will  be  at  the 
elevation  of  C,  with  A  below  B  the  amount  of  the  outer  eleva- 
tion. This  method  results  in  track  drainage  for  the  side  of  the 
street  at  the  outside  of  the  curve  and  thereby  eliminates  the  gutter 
as  a  factor  in  the  drainage. 

Interesting  Lights  on  Building  Construction- 
Theory,  Design  and  Methods 

A  Standard  Notation  for  Beam  Flexure 

The  engineer  should  be  as  familiar  with  the  application  of  the 
formula  for  beam  flexure  as  with  the  use  of  the  multiplication  table. 
Because  this  formula  is  one  of  the  most  important  in  the  whole 
subject  of  stresses,  a  standard  system  of  notation  is  desirable. 

Sixty  years  ago  Rankine  gave  in  his  "Applied  Mechanics"  the 
fundamental  equation,  M  =  pl/y.  Later  writers  have  departed 
from  the  notation  of  Rankine.  A  few  present-day  notations  will  be 
quoted. 

TEXTBOOKS  STEEL-MILL,  HANDBOOKS 

Church    M=^       Bethlehem...  .    m  =  -  =    fS 

n 

Heller   M  =  -       Cambria M  =  gj-  =  pS 

•X-i 

Kent   M  =  -       Carnegie . .  M  =  -  =   fg 

n 

Ketchum   M=  ^       Jones  &  Laughlin Mr  =  -  =   fS 

Lanza  M  =  ^       Lackawanna.  .  . .  M  =  J1  =  PS 

Ci 

Merriman M  =  - f 

c 

Trautwine    M  =  — 

It  is  true  that  variance  in  notation  causes  little  trouble  to  engi- 
neers making  constant  use  of  the  equations,  but  to  those  who  use 


20  The  Engineer  in  Field  and  Office 

them  only  occasionally  it  is  a  cause  of  annoyance.     The  writer 
suggests  the  following  as  a  standard  notation: 

A  STANDARD  NOTATION  FOR  BEAM  FLEXURE 

b  •       =  Width  of  beam,  in  inches 

d  =  Depth  of  beam,  in  inches 

Section       =  Section  cut  by  plane  perpendicular  to  longitudinal  axis  of  beam 

A  =  Area  of  section,  in  square  inches 

c  =  Distance  from  the  neutral  axis  to  the  extreme  fiber  of  section,  in 

inches 
I  =  Moment  of  inertia  of  section  about  neutral  axis,  in  inches  to  the 

fourth  power 
Iv  =  Moment  of  inertia  of  section  about  axis  parallel  to  neutral  axis,  in 

inches  to  the  fourth  power 

v  —  Distance  between  these  axes,  in  inches 

r  =  Radius  of  gyration  about  neutral  axis,  in  inches 

L  =  Length  of  span,  in  feet 

=  Length  of  span,  in  inches 

W  =  Total  load  uniform'y  distributed,  in  pounds 

w  =  Uniform  load  per  foot  of  length,  in  pounds 

=  Load  concentrated  at  any  point,  in  pounds 
M  =  Total  bending  moment  at  any  section,  in  inch-pounds 

=  Stress,  in  extreme  fiber  of  section  in  pounds  per  square  inch 

=  Section  modulus,  in  inches  to  the  third  power 

E  =  Modulus  of  elasticity,  in  pounds  per  square  inch  (steel  =  29,000,000) 

D  =  Maximum  deflection,  in  inches 

^IX    |      =  Axes  of  coordinates 

x,  y  =  Distances  of  any  point  from  axes  of  coordinates,  in  inches 

General  formulas :  Iv  =  I  +  Av2 ;  I  =  Ar2 ;  S  =  - ;  M  —  fS  =  - 

The  letter  n  is  universally  used  for  the  elasticity  ratio  between 
steel  and  concrete,  or  E8  -r-  E  c  For  this  reason  the  letter  c  is  used 
in  the  above  notation  for  the  distance  from  the  neutral  axis  to  the 
extreme  fiber  of  section. 

Stitch-Riveting  of  Struts 

In  a  built-up  member,  fastenings  between  the  parts  are  required 
only  at  points  at  which  these  parts  tend  to  move  relatively  to  each 
other.  The  usual  practice  in  designing  compression  members,  how- 
ever, is  to  fasten  the  elements  together  in  such  manner  as  to  guard 
against  any  increase  in  the  slenderness  ratio  in  any  element  of  the 
column.  Is  this  safe  enough? 

Suppose  we  have  a  strut  made  of  two  6  x  3i  x  i-in.  angles  spaced 
i  in.  apart,  of  length  96  in.  Assuming  the  two  angles  to  act  to- 
gether, r  =  1.45  in.,  and  l/r  =  66.2.  The  minimum  r  for  this  angle 
(Fig.  1)  is  0.67  in.;  hence,  if  we  put  the  pin  rivets  at  the  center 
of  length,  we  have  a  slenderness  ratio  of  48  -=-  0.76,  or  63.1,  which 
is  slightly  less  than  that  of  the  main  column. 

In  Fig.  2  is  given  an  elevation  of  the  column  looking  at  the 
face  of  the  outstanding  legs.  Here  is  shown  by  means  of  dotted 
lines  the  deflection  that  the  column  would  probably  take  if  given 
a  load  aproaching  its  maximum  capacity.  There  would  be  no 
tendency  at  the  middle  section  for  one  angle  to  move  axially  rela- 


Building  Construction 


21 


lively  to  the  other.  The  column  would  act,  as  far  as  the  deflection 
illustrated  in  Fig.  2  is  concerned,  as  a  column  of  length  equal  to 
twice  the  distance  between  pin  rivets.  In  this  case  r  =  0.97  (see 
Fig.  1).  Multiplying  0.97  by  66.2,  we  have  64.2  as  twice  the  allow- 
able spacing  of  pin  rivets.  This  calls  for  connections  at  each 
third-point  of  the  length. 


\! 


At 


4 — M 


/ 


,5 

FIG.  1 


" 


PIG.  2 


With  a  middle  rivet  only,  the  slenderness  ratio  for  parallel  axes 
is  96  -^  0.97,  or  99.  By  the  A.R.E.A.  formula  the  allowable  stress 
for  this  ratio  is  9070  Ib.  per  sq.in.,  while  the  allowable  stress  for 
the  entire  column  section,  slenderness  ratio  66.2,  is  11,370  Ib.  per 
sq.in.  Under  the  latter  load  the  angles  considered  as  independent 
elements  would  be  loaded  25.3%  over  their  allowable  stress. 

Method  of  Erecting  a  Large  Steel  Dome 

The  92-ft.  dome  of  the  Wealthy  St.  Baptist  Church,  Grand 
Rapids,  Mich.,  has  a  steel  frame  formed  by  eight  main  arch  mem- 
bers 35  ft.  in  span,  with  19-ft.  rise,  framing  into  an  octagonal 


22 


The  Engineer  in  Field  and  Office 


crown  diaphragm,  22  ft.  wide  across  the  points.  The  arches  are 
tied  together  at  the  heel  by  four  trusses  and  four  sets  of  angle  ties. 

The  arches  are  2  ft.  deep  at  the  top  and  5  ft.  at  the  outer  ex- 
tremity. Three  lines  of  beams  parallel  to  the  base  ties  carry  the 
wooden  ceiling  and  roof  joists.  The  lateral  bracing  consists  of  a 
system  of  rods  together  with  a  line  of  struts  in  the  center  of  each 
bay  at  right  angles  to  the  roof  beams.  A  steel  monitor  frame  8  ft. 
high  surmounts  the  structure. 

The  erection  procedure  was  as  follows :  A  derrick  of  the  required 
height  was  raised,  and  the  eight  sides  of  the  diaphragm  were 
riveted  up  around  its  base.  With  two  sets  of  blocks,  the  ring  was 
raised  to  the  final  elevation,  45  ft.  above  the  floor,  and  light  timber 
falsework  placed  underneath.  The  arches  were  raised  with  a  gin 
pole,  bolted  in  place,  and  the  base  ties  erected.  The  roof  beams, 
struts  and  rods  were  then  placed. 

Graphic  Solution  for  Fink  Roof  Truss 

A  simple  general  solution  for  the  graphical  analysis  of  the 
Fink  type  of  roof  truss  can  be  made  without  resorting  to  the  usual 
expedient  of  substituting  auxiliary  members  or  using  partly  ana- 


stress  Diagram 
Modified  Fink  Truss  Analyzed  Graphically 

lytical  methods.  For  example,  consider  the  modified  Fink  truss 
shown  in  the  diagram.  The  only  load  affecting  the  truss  members 
LM  and  LK  is  CD,  and  hence  these  stresses  can  be  readily  found 
graphically. 


Building  Construction 


23 


Select  any  convenient  point  M'  on  the  line  drawn  through  d  in 
the  force  diagram  parallel  to  the  rafter  of  the  truss.  Draw  M'U 
parallel  to  ML,  giving  L'  on  the  line  through  c.  Draw  UK'  parallel 
to  LK,  and  WK'  parallel  to  MN,  as  shown.  The  triangle  L'WK' 
thus  formed  gives  the  true  stresses  in  ML  and  LK,  and  also  the  true 
relative  position  of  the  point  K'  with  respect  to  the  parallel  lines 
through  c  and  d. 

The  true  position  of  K',  however,  must  be  on  a  line  through  h 
parallel  to  HK,  and  therefore  lies  at  k  in  the  stress  diagram  found 
by  K'k  drawn  parallel  to  the  rafter.  With  k  located,  the  remaining 
stresses  are  found  as  usual.  The  method  can  be  applied  to  any 
loading  and  to  unsymmetrical  Fink  trusses. 

Design  of  Concrete  Retaining  Walls 

Diagrams  for  the  designing  of  retaining  walls  are  simpler  and 
more  convenient  than  formulas.  For  the  purpose  of  illustration 


"TYPICAL  SECTION       HOR.PRESDIAGRAM 

I 


08/0 
Values  of  Various -Functions. 


Fig.  1.    Dimensions  and  Quantities — Walls  Without  Surcharge 

two  cases  will  be  considered — (1)  that  of  a  gravity  wall  without 
surcharge,  and  (2)  that  of  a  gravity  wall  with  railroad  surcharge 


24 


The  Engineer  in  Field  and  Office 


of  Cooper's  E-55  loading,  with  center  line  of  track  8  ft.  6  in.  from 
the  face  of  the  coping. 

A  gravity  retaining  wall  of  the  type  shown  in  Fig.  1,  which  is 
safe  against  overturning,  will  also  be  safe  against  sliding  and 
crushing  the  masonry,  and  with  a  suitable  toe  may  be  built  upon 
any  ordinary  foundation.  We  may  then  assume  a  minimum  factor 
of  safety  against  overturning  and  find  the  widths  of  the  base  for 
various  heights.  Assuming  that  the  slope  of  repose  of  the  filling 


TYPICAL  SECTION     HOR.PRESJ)IASRAMS 


Values  of 'Various  Functions 


Fig.  2.    Dimensions  and  Quantities — Walls  with  Surcharge 

is  li  to  1,  the  horizontal  pressure  on  a  vertical  plane  is,  according 
to  Rankine,  0.286  of  the  vertical  pressure.  Earth  has  been  taken 
at  100  Ib.  per  cu.ft.,  and  concrete  at  150  Ib.  per  cubic  foot. 

The  diagram,  Fig.  1,  gives  the  width  of  the  base  of  the  neatwork 
for  a  factor  of  safety  against  overturning  of  exactly  2.  Using  a 
minimum  footing  projection  of  6  in.  at  the  toe  and  1  ft.  at  the  heel, 
the  entire  wall  always  has  a  factor  greater  than  2.  The  maximum 
compressive  stress  in  the  concrete  is  90  Ib.  per  sq.in.,  and  the  wall 
will  be  on  the  verge  of  sliding  when  the  coefficient  of  friction  is 
about  0.3. 

The  dead-load  for  the  case  of  a  surcharge  wall  is  considered  the 
same  as  in  case  1.  The  live-load  has  been  taken  as  11,000  Ib.  per 
lin.ft.  of  track,  distributed  from  the  base  of  rail  and  end  of  tie 


Building  Construction 


25 


as  shown  in  Fig.  2,  the  limits  of  the  distribution  being  the  face 
of  the  wall  and  a  line  6  ft.  6  in.  from  the  center  line  of  the  track 
midway  between  tracks,  assuming  a  second  track  13  ft.  from  the 
first.  The  ratio  of  horizontal  to  vertical  live-load  pressure  has 
been  taken  the  same  as  for  the  dead-load.  The  portion  of  the 
live-load  pressure  uniformly  distributed  over  the  width  6  has  been 
assumed  as  adding  to  the  weight  and  stability  of  the  neatwork, 
while  for  the  entire  wall  the  width  &  +  1  nas  been  used.  No  dis- 
tribution has  been  considered  beyond  the  plane  of  the  face  of  the 
wall,  no  matter  what  the  length  of  the  toe  might  be. 

The  horizontal-pressure  diagrams  are  shown  in  Fig.  2,  and  the 
widths  of  the  base  of  the  neatwork  for  dead-load  and  live-load  are 
plotted  on  the  diagram,  as  are  also  the  values  for  dead-load  only, 
The  factor  of  safety  against  overturning  for  the  neatwork  is  ex- 
actly 2.  The  maximum  compression  in  the  concrete  is  103  Ib.  per 
sq.in.,  and  the  wall  will  be  on  the  verge  of  sliding  when  the  co- 
efficient of  friction  is  about  0.3,  as  before.  The  limiting  values  for 
the  height  of  wall  have  been  selected  so  as  to  make  the  diagram 
general  for  all  heights  likely  to  be  encountered.  It  is  not  intended, 
however,  to  indicate  that  gravity  walls  of  the  extreme  heights 
shown  could  be  economically  built.  For  estimating  purposes,  the 
quantities  for  the  higher  walls  would  be  on  the  safe  side. 

Forms  Designed  To  Leave  Storage  Space 

As  the  street  had  to  be  kept  open  for  traffic,  storage  for  1250 
yd.  was  provided  in  a  building  recently  erected  in  Toronto,  Ont., 


E^lS*  Floor 


STORAGE 


Wide  Space  Between  Bents  for  Storage 

by  employing  specially  designed  form  supports.     The  use  of  bents 
with  a  wide  space  between  them  was  made  possible  by  unusual  story- 


26  The  Engineer  in  Field  and  Office 

height  of  the  first  floor— 18  ft.  9  in.— and  the  fact  that  there  was 
no  basement.  The  bents  were  11  ft.  apart  at  the  top  and  17  ft. 
apart  at  the  bottom,  this  construction  being  carried  over  an  area 
six  bays  wide  and  three  bays  deep.  The  fourth  bay,  in  front  of 
the  aisles  thus  formed,  served  as  a  connecting  passage,  and  bents 
were  built  lengthwise  of  it  for  the  full  width  of  the  six  bays.  Teams 
would  drive  into  any  of  the  first  five  bays,  dump  and  return  to 
the  street  by  way  of  the  connecting  passage  and  the  sixth  bay, 
which  was  used  for  return  only. 

Each  storage  space  thus  provided  had  a  length  of  about  75  ft. 
and  a  width  of  17  ft.,  giving  a  storage  capacity  of  250  yd.  Two 
bays  were  reserved  for  sand,  two  for  stone,  and  one  for  cement. 

Gypsum  Roof  Slabs  of   10-Ft.   Span 

A  roof  covering  composed  of  gypsum  T-beam  slabs  10  ft.  long, 
having  a  clear  span  of  9  ft.  8  in.,  is  a  feature  of  a  steel-frame 
building  190  x  200  ft.  recently  erected  at  Racine,  Wis.  These  long 
slabs,  designed  as  the  outcome  of  numerous  tests  made  at  the 
University  of  Illinois,  are  of  T-section,  15  in.  wide  and  8  in.  deep, 
with  a  thickness  of  H  in.  for  the  top,  or  flange,  and  2i  in.  for  the 
rib.  The  ends  are  closed  by  diaphragms  15  in.  wide  and  2  in.  thick. 
Each  beam  has  two  §-in.  rods  in  the  bottom  of  the  rib,  one  of  these 
being  bent  up  at  the  ends  as  a  shear  rod  and  looped  so  as  to  increase 
the  value  of  the  bond  stress.  In  the  top  flange  is  embedded  a  steel- 
wire  mat  of  No.  14  gage  and  4-in.  mesh.  The  weight  is  16  to  17 
Ib.  per  sq.ft.  The  joints  are  plastered  on  the  outer  surface. 

These  beams  were  made  at  the  site,  in  wood  forms,  at  the  rate  of 
about  300  sq.ft.  per  hr.  They  only  required  15  min.  to  set,  from 
the  time  the  mold  was  poured  until  the  forms  were  knocked  down, 
and  were  erected  in  place  and  walked  upon  within  three  hours  after 
being  poured.  They  were  designed  to  carry  a  uniformly  distributed 
live-load  of  50  Ib.  per  sq.ft.  with  a  safety  factor  of  4.  Tests  of  five 
sample  beams  24  hr.  old  were  made  with  loads  of  2200  and  2400  Ib., 
or  200  to  218  Ib.  per  sq.ft.,  with  respective  deflections  of  0.034  and 
0.070  in.  The  total  loads  were  then  increased  to  3500  Ib.,  causing 
slight  horizontal  shear  cracks  to  appear,  but  without  other  signs 
of  failure. 

In  the  roof  construction  these  slabs,  or  beams,  are  carried  by 
light  steel  trusses  for  the  saw-tooth  portions  and  by  steel  purlins, 
etc.,  for  the  flat  portions,  all  of  the  supporting  steel  being  spaced 
10  ft.  c.  to  c.  In  general  the  flat  roof  portion  has  a  pitch  of  1J  in 
12,  while  the  saw-tooth  construction  pitches  about  7£  in  12.  When 


Building  Construction 


21 


a  flat  ceiling  effect  is  desired,  instead  of  the  ribbed,  or  beam,  ceiling 
formed  by  these  T-beams,  the  slabs  may  be  of  H-section,  with  the 
top  and  bottom  flanges  of  equal  width.  These  weigh  from  22  to  24 
Ib.  per  sq.ft.  for  the  live-load  noted  above.  In  such  a  roof  now  being 
erected  the  beams  weigh  22  Ib.  per  sq.ft. 

Crane  Runway  Columns  Carry  Roof 

A  yard  crane  with  supports  designed  to  carry  a  roof  over  the 
yard  is  an  interesting  feature  of  the  new  foundry  plant  for  the 
James  A.  Brady  Co.,  at  Chicago.  The  material  yard  is  between 
two  buildings  and  is  served  by  a  5-ton  electric  traveling  crane. 


tf 


~lLaw.«i 


rtsnj 


.........^ 


**4RnkiM''ie  ?'-(,*         ^"Cross  Bracing 

i.-*6v.-y*-v.- v»i      T*t5CW^V4^c     &  r^i  ^% 

fiSf^r^ 
T/iis  Runway  for  a  Yard  Crane  Is  Designed  To  Carry  a  Roof 


Elevation     of 
Cross    Bracing 


The  crane  runway  consists  of  20-in.  I-beams  carried  by  brackets 
upon  columns  about  42  ft.  high.  The  runway  is  180  ft.  long,  with 
columns  and  trusses  spaced  20  ft.  c.  to  c.  The  columns  are  of  H- 
section,  with  a  10-in.  web  plate  and  four  angles  5  x  3£  in.  Longi- 
tudinal bracing  is  provided  by  a  double  line  of  6-in.  channels,  form- 


28 


The  Engineer  in  Field  and  Office 


ing  an  inverted  T-section,  between  the  columns,  at  a  height  of  15  ft. 
above  the  ground.  Horizontal  and  vertical  diagonal  bracing  is 
provided  in  three  of  the  bays. 

Temporary  Stringers  Carry  Elevated  Tracks 

An  opening  4£  ft.  wide  in  the  structure  of  the  Metropolitan 
Elevated  Ry.,  Chicago,  was  necessitated  by  changes  in  the  bents 
and  spans  where  the  line  crosses  the  new  Union  Station.  One  new 
bent  was  4£  ft.  from  the  old  one,  and  the  adjacent  girder  span  had 


/Pt:to"x\ 


i 


NEYfBEKT 

^6- — >|<~/0^ 

NEWPAHELSPUCED  TO 
GIRDER* 


Stringers  Carrying  Track  Rails  Across  Gap  in  Elevated 
Railway  During  Alterations 

to  be  lengthened  by  splicing  on  an  additional  panel.  Traffic  could 
not  be  interrupted;  and  while  the  work  was  being  done,  each  rail 
was  carried  across  the  gap  in  a  stringer  of  trough  section,  the  ends 
of  the  stringer  resting  on  the  track  ties  at  each  side  of  the  opening, 
as  shown  in  the  accompanying  drawing. 

Tar  Paper  Deadens  Noise  of  Trucks 

To  deaden  the  noise  from  passing  trucks  rumbling  over  a  con- 
crete floor,  a  factory  in  Norwich,  Conn.,  has  successfully  used  a 
heavy  tar  paper  pasted  to  the  floor  by  paint.  The  method  of  appli- 
cation is  as  follows:  The  floor  is  first  given  one  coating  of  a  gray 
cement  paint.  On  the  following  day,  when  the  paint  is  thoroughly 
dry,  a  second  coat  is  applied.  At  the  same  time  one  side  of  a  five- 


Building  Construction  29 

ply  tar  paper  is  painted;  and  when  both  paper  and  floor  are  still 
wet,  the  paper  is  carefully  laid  wet  side  down  on  the  floor  and 
rolled  with  either  a  roller  or  wide-tired  truck  until  all  signs  of 
air  pockets  beneath  the  paper  disappear.  The  surface  seems  to 
improve  with  age  and  very  effectively  reduces  noise  at  a  low  cost. 

Excess  Volume  of  Flared  Column  Heads 

In  computing  the  volume  of  the  capital  or  flare  in  a  column  for 
girderless  concrete  floor  construction,  a  simple  method  is  to  deter- 
mine the  volume  of  the  flare  outside  of  the  column  shaft,  which  is 
itself  figured  as  running  from  the  top  of  one  floor  slab  to  the 
bottom  of  the  next  slab  above.  Formulas  for  this  additional  volume 
have  been  deduced  by  Edgar  H.  Mosher,  of  Washington. 

Where  V  =  volume  of  concrete  to  be  added  to  the  volume  of  a 
straight  column  figured  to  the  bottom  of  the  slab;  D,  diameter  of 
flare  or  top  of  capital,  and  d,  diameter  of  column,  the  formulas  are 
as  follows: 
For  square  columns, 


T/  —  V^         **/    v^ 
6 

For  round  columns, 

_  (D-  dY(D 
7.63 

For  octagonal  columns, 


7.23 

These  formulas  are  deduced  from  the  truncated  cone  formula, 
assuming  45°  to  be  the  slope  of  the  flare. 

Special  Forms  For  Light  Floor  System 

The  designers  claim  a  considerable  saving  in  weight  and  hence 
in  cost  over  any  other  fireproof  floor  of  equal  strength  for  a  floor 
consisting  of  rows  of  small  concrete  beams  or  joists  of  T-shape 
poured  monolithically  with  their  supporting  beams  or  girders 
between  forms  made  up  of  spacing  members  or  boxes  of  wood  and 
cores  of  bent  sheet  metal.  The  accompanying  perspective  shows  the 
general  layout  of  the  system,  which  may  be  used  either  on  steel- 
frame  or  on  reinforced-concrete  buildings. 

In  building  the  floor,  a  line  of  struts  is  placed  in  each  lower 
T-beam  and  capped  with  plank  that  serve  as  beam  bottoms.  On 


30 


The  Engineer  in  Field  and  Office 


these  plank  as  joists  is  then  laid  expanded  or  ribbed  metal  that 
forms  a  ceiling  base.  Then  metal  forms  bent  to  the  shape  of  one 
side  of  the  T-beam  are  placed  over  each  plank  and  held  in  position 
by  properly  cut  brace  boards  between  beams  and  by  stiffener  planks 
along  the  top.  In  the  T-form  thus  made,  the  proper  reinforcing  is 
placed  and  the  concrete  poured  to  make  the  T-beam. 


Perspective  of  Layout  of  System 

When  these  beams  have  set,  the  bracing  boards  are  knocked  out 
and  the  beam  metal  forms  released  to  be  taken  upward  and  used  on 
the  next  floor  above.  The  beams  are  then  overlaid  with  another 
sheet  of  expanded  metal,  and  the  usual  cinder  concrete  floor  is 
placed.  For  the  upper  (floor)  layer  a  fireproof  board  could  be  used 
in  place  of  expanded  metal. 


Building  Construction 


31 


Concrete  Cantilever  Beams 

Cantilever  beams  of  reinforced  concrete,  designed  to  support  an 
outside  entranceway  leading  from  a  bridge  over  the  Fox  River,  and 
flat-slab  floors  without  column  capitals,  to  facilitate  the  placing  of 
partitions,   are  two   principal  features   in  a 
recently  completed  eight-story  hotel  at  Aurora, 
111.     Above   the   cantilever   entranceway   for 
three  panels  of  its  length  the  mezzanine  floor 
was  also  extended  over  the  river  on  columns 
supported  by  the  cantilever  beams,  the  heaviest 
of  which  is  here  illustrated  in  detail. 

The  building  is  70  x  100  ft.  in  plan,  with  its 
main  entrance  on  the  south  side  and  with  a 
second  entrance  at  the  northwest  corner,  where 
!     the  hotel  adjoins  the  new  bridge.     This  out- 

>  side  entrance,  which  is  indicated  by  the  photo- 
.     graphs,  cantilevers  10  ft.  over  the  river,  and 

>  results  in  saving  space  within  the  building 
1     lines  to  such  an  extent  that  one  more  store 

>  is  now  available  which  would  have  been  elim- 
?     inated  if  this  scheme  had  not  been  adopted. 

In  order  to  facilitate  the  locating  and  rear- 

>  ranging  of  partitions,  flat-slab  floors  supported 
^     on  square  columns  designed  to  eliminate  the 
I     column  capitals   usually  used  were  adopted. 
1     The  first-floor  slab  is  7  in.  thick;  the  slabs 
5     used  on  the  upper  floors  are  6  in.  thick.    No 

beams  were  required  except  the  cantilevers 
already  described  and  beams  for  window  lin- 
tels and  to  frame  around  elevator  and  stair 
openings.  The  design  of  the  slabs  proved  to 
be  economical,  four-way  reinforcement  of  i-in. 
rods  being  used. 

The  forms  for  the  cantilever  beams  were 
also  constructed  as  a  cantilever  timber  frame- 
work, owing  to  the  fact  that  the  river  bottom 
beneath  the  outer  ends  of  these  cantilevers  consists  of  boulders,  dirt 
and  rubbish,  making  it  impossible  to  drive  piling  on  the  shore. 


32  The  Engineer  in  Field  and  Office 

Window-Frame  Clamp  Saves  Time  and  Room 

When  setting  window  frames  in  stone  or  terra  cotta  faced  build- 
ings, considerable  time  can  be  saved,  as  well  as  avoiding  the 
obstruction  of  floor  space  with  long  braces,  by  using  the  clamp 
shown  in  the  photograph.  The  long  piece  is  a  2  x  4  to  each  end  of 
which  is  nailed  at  right  angles  a  piece  of  board  about  6  in.  long. 
Five  nails  are  used  in  each  end.  The  distance  between  the  inside 
edges  of  these  boards  is  1  in.  greater  than  the  distance  between  the 
outer  face  of  the  jamb  and  the  face  of  the  brick  backing. 

The  window  frame  is  set  up  when  the  first  jamb  stones  have 
been  placed,  after  which  one  of  the  braces  is  placed  at  each  side. 


Clamp  Can  Be  Quickly  Adjusted 

The  braces  may  be  tightened  with  wedges,  or  by  driving  down  one 
side  until  the  brace  sets  tight.  They  will  hold  the  window  frame 
securely  in  place  until  the  brick  work  is  finished. 

Anchor  High  Form  to  Face  of  Stone  Retaining  Wall 

Anchor  bolts  were  used  as  shown  in  the  sketch  to  secure  the 
form  for  facing  with  concrete  an  old  retaining  wall  of  dry  masonry 
which  supports  a  section  of  a  railroad  line  that  runs  along  the  face 
of  a  cliff  about  100  ft.  high.  The  wall  extends  down  to  a  ledge  about 


building  Construction 


33 


50  ft.  below  the  track.  This  ledge  was  about  10  ft.  wide  outside 
the  old  stone  wall,  and  the  working  space  was  still  further  reduced 
by  the  thickness  of  the  new  wall,  which  was  4  ft.  at  the  bottom  and 
18  in.  at  the  top.  The  anchor  bolts  were  of  i-in.  round  rods,  one 


High  Form  on  Cliff  Face  Anchored  to  Old  Wall 


end  of  each  of  which  was  split  for  about  2  in.  to  receive  a  wedge. 
Holes  5  in.  deep  were  drilled  into  the  stone  of  the  old  wall,  into 
which  the  split  ends  of  the  rods,  with  small  wedges  inserted,  were 
driven. 

As  it  was  impossible  to  remove  the  bolts  after  the  forms  were 
stripped,  they  were  nicked  with  a  hacksaw  about  1  in.  inside  the 
face  of  the  form.  When  the  forms  were  taken  off,  a  few  sharp  blows 
with  a  hammer  knocked  off  the  ends  of  the  bolts  inside  the  surface, 
and  the  holes  were  plastered  up. 

Some  Capital  Things  in  Foundation  Work 

Use  Pier  Form  as   Inside  Cofferdam 

The  pier-shaft  form  was  set  under  water  and  did  double 
duty  as  inside  cofferdam  and  concrete  form  in  constructing  the 
shaft  of  the  pier  for  the  Division  St.  bridge  in  Spokane.  The 
cofferdam  had  been  sealed  under  water,  and  two  layers  of  bracing, 
which  had  been  required  during  the  driving  of  the  sheeting  and 
the  placing  of  the  seal,  were  then  removed.  This  work  was  done 
by  a  diver,  taking  out  the  crossbraces  but  leaving  the  tie-rods  in 
place.  The  form  for  the  pier  shaft,  which  was  built  of  2  x  8-in. 


34  The  Engineer  in  Field  and  Office 

tongue  and  groove  sheeting,  placed  vertically,  was  stood  up  in 
the  cofferdam,  brought  to  line  and  well  braced  inside  with  the 
help  of  the  diver.  The  cost  of  this  form  exceeded  by  a  surprisingly 
small  amount  that  of  similar  work  done  in  the  open. 

The  extra  width  of  the  cofferdam  and  the  batter  of  the  pier 
left  a  space  28  in.  wide  at  the  top  and  16  in.  wide  at  the  bottom 
between  the  outside  of  the  form  and  the  piles.  Around  this 
space,  about  a  foot  of  concrete  was  deposited  under  water,  sealing 
any  leaks  between  the  concrete  and  the  bottom  of  the  form. 
This  space  was  then  carefully  puddled  with  a  mixture  of  gravel, 
clay  and  manure,  gravel  being  used  to  save  the  clay,  which  was 
expensive.  This  formed  a  puddle-wall  cofferdam  for  practically  the 
cost  of  a  single  line  of  sheeting,  plus  the  cost  of  placing  the 
puddle  material.  Having  tongue  and  groove  walls  on  both  sides, 
the  dam  proved  very  tight.  The  method  also  saved  considerable 
time,  the  initial  time  for  constructing  the  cofferdam  being  much 
less  than  if  it  had  been  made  with  two  rows  of  sheeting,  and  the 
form  and  puddle  work  being  carried  out  while  the  concrete  seal 
was  setting,  which  time  would  have  been  lost. 

A  pump  was  put  inside  the  form,  the  space  unwatered  and  the 
seal  concrete  carefully  cleaned.  The  bracing  inside  the  form  was 
taken  out  as  the  pier  concrete  came  up. 

Cofferdam  on  Uneven  Rock  Bottom 

A  cofferdam  of  Wakefield  sheet  piles,  which  was  framed  and 
put  in  place  as  a  skeleton  before  setting  most  of  the  piles,  was 
used  successfully  on  the  practically  bare  and  very  irregular  rock 
bottom  at  the  site  of  one  of  the  piers  for  the  new  Division  Street 
bridge  in  Spokane. 

This  bridge  was  a  structure  70  ft.  wide  and  about  600  ft.  long, 
consisting  of  three  concrete  arch  spans  with  concrete  viaduct 
approaches.  The  pier  between  the  second  and  third  arch  spans 
was  located  in  water  which  was  23  ft.  deep  at  the  lowest  point, 
at  low-river  stage.  Being  only  a  short  distance  above  the  falls, 
there  was  a  strong  current  at  the  bridge  site.  Soundings  showed 
that  the  site  of  the  pier  was  crossed  diagonally  by  a  vertical 
ledge,  the  bare  rock  at  the  downstream  end  of  the  pier  being  about 
15  ft.  below  the  water,  while  the  rock  at  the  upstream  end,  where 
the  depth  was  greatest,  was  covered  with  3  or  4  ft.  of  sand  and 
fine  gravel.  It  was  planned  to  construct  the  pier  on  a  concrete 
seal  placed  on  the  rock  under  water,  and  it  was  necessary  to  use 
a  cofferdam  because  the  irregular  bottom  made  a  crib  out  of  the 
question. 


Foundations 


35 


The  cofferdam,  the  skeleton  of  which  was  built  in  the  water, 
towed  to  place  and  set  before  the  insertion  and  driving  of  most 
of  the  piles,  was  made  2  ft.  wider  and  3  ft.  longer  than  the  base 
of  the  pier.  Three  layers  of  outside  and  inside  waling,  between 
which  the  sheeting  fitted,  were  framed  and  spaced  at  the  proper 


Frame  for  Sheet-Pile  Cofferdam  Supported  by  Driving 
Down  Slotted  Piles 

distance  apart  by  bolting  them  to  sheet  piles  placed  at  each  cross- 
brace,  16  ft.  apart.  In  these  piles,  through  which  passed  the  long 
bolts  shown  in  the  drawing,  which  held  each  layer  of  bracing 
together,  were  cut  H-in.  by  4-ft.  slots  to  permit  driving  them  after 
the  dam  was  placed.  So  that  they  would  not  bind  after  the  frame 
had  been  drawn  tight  with  the  long  bolts,  1-in.  pipe  sleeves,  \ 


36  The  Engineer  in  Field  and  Office 

in.  longer  than  the  thickness  of  the  pile,  were  placed  around  each 
end  of  each  long  bolt  in  these  slots.  These  sleeves,  bearing  against 
plate  washers  inside  the  rangers,  prevented  their  being  clamped 
tightly  to  the  pile.  The  rectangular  part  of  the  frame  was  12  x  73 
ft.  inside  the  sheeting,  but  the  total  inside  length  of  the  cofferdam 
was  89  ft.  on  account  of  the  two  pointed  nose  sections. 

In  addition  to  the  posts  shown  in  the  drawing  between  the 
three  tiers  of  bracing,  the  frame  was  X-braced  for  its  entire 
length  in  a  vertical  plane,  and  each  layer  was  also  X-braced  with 
2  x  6-in.  planks. 

Pile  bents,  braced  above  and  below  water,  had  been  driven 
out  to  the  site  of  the  pier  for  construction  purposes  and  to  serve 
later  as  a  support  for  the  arch  centering.  Extending  the  entire 
length  of  the  pier  and  about  3  ft.  from  it,  this  falsework  afforded 
a  good  anchorage  along  one  side  of  the  dam.  On  this  falsework 
was  a  large  stiff -leg  derrick.  ,The  frame  was  moored  and  held 
plumb  by  the  derrick  while  being  weighted  with  bags  of  sand 
until  it  grounded  on  the  downstream  end.  The  upstream  end 
was  weighted  to  float  level  with  the  lower  end,  after '  which  the 
slotted  piles  were  driven,  where  the  4-ft.  slots  were  long  enough 
to  permit  it,  to  a  bearing.  These  piles  were  then  bolted  securely 
to  the  frame,  serving  as  legs  to  hold  it  in  place  while  the  remaining 
Wakefield  piles  were  set  around  it.  Special  piles  were  made  where 
necessary  to  secure  tight  closures. 

When  all  the  bays  were  filled,  the  piles  were  driven  to  rock  with 
a  drop  hammer,  handled  in  swinging  leads  by  the  derrick,  and 
bolted  to  the  frame,  more  weight  being  added  to  overcome  the 
increasing  buoyancy.  The  piles  were  built  up  of  3  x  12-in.  plank, 
surfaced  one  side  and  one  edge,  and  were  dry  when  placed,  so  as 
to  swell  tight.  The  only  openings  were  now  the  slots,  the  irregulari- 
ties on  the  bottom,  and  in  some  cases  a  hole  as  much  as  3  or  4 
ft.  high  where  the  slots  did  not  permit  driving  a  pile  to  bottom. 
The  large  holes  and  slots  were  boarded  up  by  a  diver. 

Concrete  Bases  for  Old  Bridge  Piles 

Replacing  piling  under  wood  bridges  still  in  fairly  good  repair 
as  to  caps,  joists  and  flooring  has  been  one  of  the  big  items  of 
expense  in  Sedgwick  Co.,  Kan.,  for  years  past.  The  county  is  now 
doing  a  great  deal  of  permanent  bridge  and  culvert  construction, 
but  there  are  still  many  pile  bridges  over  the  larger  streams  which 
will  have  to  be  maintained  for  a  number  of  years  to  come.  To 
reduce  this  expense  concrete  bases  have  been  placed  under  the  piles 


Foundations 


37 


that  have  rotted  dangerously  at  the  ground  line.  Replacing  a  pile 
always  necessitates  tearing  up  the  deck  of  the  bridge,  removing 
at  least  two  or  three  joists  and  frequently  the  cap,  and  sometimes 
requires  falsework  for  the  piledriver.  Where  it  has  been  possible 
to  work  on  the  ground  and  there  was  soil  that  would  stand,  a 
repair  gang  has  put  in  a  concrete  base,  retaining  the  upper  part  of 
the  old  pile.  The  chief  difficulty  has  been  to  get  down  past  the 
root  of  the  pile.  This  has  been  surmounted  in  most  cases  either 
by  pulling  or  digging  out  the  lower  part  of  the  pile,  or  by  moving 
the  top  of  the  pile  slightly. 


-.•own/e 

^•Lagscrews 


Base  for  Old  Pile 

A  7-in.  post  augur  drills  the  holes  to  a  depth  of  5  to  8  ft. 
Sometimes  the  holes  are  reamed  out  by  a  "jabbing  digger"  or  a 
pile  spade,  which  operation  allows  a  mushroom  base  to  be  formed. 
Where  shale  or  a  very  hard  clay  subsoil  is  encountered — even 
though  only  a  few  feet  under  the  surface — no  attempt  has  been 
made  to  penetrate  it;  nor  have  these  holes  been  put  down  or  bases 
built  where  there  is  surface  water.  In  a  number  of  instances 
where  sand  was  struck  below  the  surface,  this  sand  was  thoroughly 
mixed  with  a  sackful  or  less  of  cement,  thus  forming  a  base  that 
holds  satisfactorily.  This  construction,  however,  is  never  attempted 
except  where  the  surface  soil  is  firm  and  hard. 

After  filling  the  hole  with  concrete,  a  round  sheet-metal  form, 
a  little  larger  in  diameter  than  the  hole,  is  placed  at  the  surface. 
In  the  form  three  or  four  iron  straps  are  placed,  so  that  they  will 


38 


The  Engineer  in  Field  and  Office 


project  8  to  12  in.  above  the  concrete.  Each  strap  is  drilled  for 
two  lagscrews,  and  the  straps  are  placed  so  that  the  pile  slips 
between  them. 

The  top  of  the  base  is  pressed  down  or  cupped,  using  either  a 
wood  form  or  a  trowel.  This  device  helps  to  keep  the  pile  firmly 
in  place.  The  concrete  sets  for  48  hours  before  the  pile,  which  is 
secured  with  the  lagscrews,  is  placed.  Under  favorable  conditions 
this  method  of  repair  is  much  cheaper  than  replacing  old  piles 
with  new,  and  it  seems  to  be  more  lasting. 

Cushion  Blocks  Reinforced  by  Vertical  Rods 

With  a  specially  designed  cast-steel  hood  fitted  with  a  reinforced 
wood  plug  rapid  driving  of  steel  sheet  piles  has  been  accomplished  at 
Dam  No.  39,  Ohio  River.  As  many  as  fifty-four  25-ft.  Lackawanna 
piles  have  been  driven  with  one  driver  in  one  8-hour  shift.  The 


Woodjkjshion 


Secrion   A-  '•'-> 
Round  Pins  Transmit  Blows  and  Save  Cushion  Block 

hood  is  so  constructed  that  either  straight  web,  gusset,  corner  or  T 
piles  can  be  fitted  into  the  grooves  in  its  under  side.  It  is  held  to 
the  hammer  by  wire  lines  or  by  rods  passing  through  If  in.  holes. 
A  circular  hole  in  the  head  permits  an  oak  block  to  be  inserted  as 
a  cushion  to  receive  the  direct  blow  of  the  hammer.  This  block,  11 
in.  in  diameter,  is  bound  with  a  1  x  2£-in.  iron  collar.  This  prevents 
it  from  mashing  up  at  the  top.  Holes  are  drilled  in  the  block  to 
receive  l-in.  round  iron  pins  which  transmit  the  blow  from  hammer 
to  pile  follower. 


Foundations 


Spreading  Piles  Pulled  Back  By  Turnbuckles 

The  column  footings  for  the  three-track  elevated  railway  along 
Stillwell  Ave.,  Brooklyn,  N.  Y.,  were  constructed  across  a  swamp  in 
which  the  mud  varied  in  depth  from  15  to  30  ft.  The  piers  were 
supported  on  spruce  piles  30  in.  on  centers,  which  were  driven  to 
refusal  with  a  2000-lb.  drop  hammer  into  the  sand  and  gravel  under- 
lying the  mud. 


Fill  made        p "^ *6'' 

torefain      fl    ft          2'/&Wire 

Footings    M$\       ;  Cables _         _CinderFHI_ 


Spreading  Footings  Restored  by  Turnbuckles 

Over  the  greater  part  of  this  swamp  there  was  an  ash  fill  6  or 
8  ft.  in  depth,  which  had  been  in  place  some  6  years.  This  fill 
served  to  give  lateral  stability  to  the  footings.  At  one  point, 
however,  near  a  creek,  there  was  no  fill  on  the  original  salt  marsh. 
Here  it  was  brought  home  forcibly  to  the  engineers  that  piles 
driven  in  soft  material,  although  able  to  support  the  load  brought 
upon  them,  have  little  lateral  resistance,  and  that  a  structure  sup- 
ported on  piles  under  such  conditions  is  liable  to  injury  if  a 
horizontal  force  is  brought  to  act  on  them. 

The  piers  at  this  point  are  7  ft.  2  in.  by  9  ft.  8  in.  in  plan,  sup- 
ported by  12  piles  each ;  they  carry  a  load  of  145  tons.  The  contractor 
laid  a  standard-gage  track  on  a  cinder  fill  about  2  ft.  deep  between 
the  two  lines  of  piers,  and  used  a  50-ton  locomotive  and  flat-cars 


40  The  Engineer  in  Field  and  Office 

to  haul  structural  steel.  The  load  of  35  tons  per  car  axle  which  was 
thus  brought  to  bear  on  the  underlying  mud  forced  it  out  laterally 
against  the  piers.  It  sprung  the  piles  and  spread  the  opposite  piers 
apart  2£  in.  in  the  bent  in  question. 

In  order  to  repair  the  damage,  two  I-in.  wire  cables  with  turn- 
buckles  were  passed  around  the  piers.  By  drawing  these  up,  it 
was  possible  to  pull  the  piers  back  to  correct  position.  An  earth  fill 
was  made  around  the  footings  to  retain  them  in  their  proper  position, 
the  cables  being  left  in  place  as  an  additional  precaution. 

Freezing  Ground  Acts  Like  Hydraulic  Jack 

Some  16-ton  concrete  piers  in  a  Middle-West  city  were  heaved 
this  past  winter  by  as  much  as  3  in.  and  subsequently  settled  back  to 
their  original  elevation.  This  most  unusual  and  extreme  condition 
cannot  be  explained  by  ordinary  frost  action,  but  can  be  accounted 
for  by  the  piers  becoming  the  pistons  of  hydraulic  jacks  in  which 
frost  produced  the  moving  pressure. 

This  occurred  where  a  bridge  was  being  built  in  the  course  of 
track-elevation  work.  Some  heaving  also  occurred  at  an  adjacent 
street.  The  abutments  and  piers  at  both  streets  were  poured  during 
the  summer  and  autumn  of  1916.  The  bridge  steel  could  not  be 
placed  until  the  following  season,  hence  the  piers  and  abutments 
carried  no  load  other  than  their  own  dead  weight. 

Where  the  most  heaving  occurred,  only  the  center  and  south  rows 
of  piers  were  appreciably  affected.  The  north  row  was  fairly  well 
drained  and  much  drier  than  those  to  the  south  where  all  conditions 
were  favorable  to  waterlogging.  The  bottom  of  the  north  side  piers 
was  about  4i  ft.  below  the  ground  surface,  of  the  center  piers  4  ft., 
and  of  the  south  piers  3i  ft. 

The  discovery  was  made  in  March,  1917,  that  the  south  row  of 
piers  had  heaved  by  amounts  varying  from  0.07  to  0.22  ft.  The 
center  row  showed  heaving  ranging  from  0.01  to  0.09  ft.  The  north 
row  showed  nothing  in  excess  of  i  to  i  in.,  most  of  which  could 
have  been  in  the  original  setting. 

After  this  was  discovered,  levels  were  taken  at  intervals  of 
3  to  5  days.  As  the  ground  thawed  the  piers  settled  back  into 
position  until  the  highest  corner  of  any  grillage  was  but  0.06  ft., 
or  |-in.  above  what  it  should  be.  A  settlement  of  as  much  as  0.18 
ft.  or  2i  in.  is  shown. 

The  usual  explanation  would  be  that  the  frost  penetrated  to  a 
level  below  the  bottom  of  the  piers  and  heaved  them  by  direct  action, 
but  this  does  not  seem  adequate  for  the  following  reasons: 


Foundations 


41 


(1)  It  is  very  doubtful  if  the  frost  penetrated  as  low  as  the 
bottom  of  the  piers. 

(2)  If  the  frost  did  penetrate  to  below  the  bottom  of  the  piers 
there  could  not  have  been  more  than  from  6  in.  to  1  ft.  of  frost 
at  the  most.    This  thickness  of  frost  could  not  possibly  heave  a  pier 
nearly  3  in.    Water  expands  about  ^  of  its  volume  upon  freezing. 
The  expansion  of  water-soaked  soil  would  not  be  greatly  in  excess 
of  this  if  as  much.     That  would  mean  but  0.1  ft.  upheaval  for  a 
whole  foot  of  frost  under  the  pier. 

If  the  pier  is  considered  analogous  to  the  piston  of  a  hydraulic 
jack  and  the  water  or  semi-fluid  mud  is  forced  under  the  pier  by 
the  pressure  from  the  freezing  expanding  strata  nearer  the  surface, 
the  action  can  be  understood. 


Piers  Were  Plungers  in  a  Big  Natural  Jack 

Let  AB  represent  the  surface  of  the  ground.  Suppose  the 
ground  to  freeze  to  a  depth  d,  such  that  the  frozen  layer  becomes 
rigid  and  unyielding.  Let  the  frost  then  penetrate  to  an  additional 
depth  e.  The  layer  e  expands  in  freezing.  It  exerts  a  pressure  both 
upward  and  downward.  The  frozen  mass  d  is  unyielding  and  if 
the  weight  of  the  pier  is  less  than  the  force  required  to  break  the 
rigid  layer,  the  water  and  semi-fluid  clay  will  be  forced  upward 
like  a  piston.  Such  an  action  would  account  for  any  amount  of 
heaving. 

At  the  other  location,  where  there  is  practically  no  depression, 
only  3  or  4  piers  out  of  a  total  of  42  were  found  to  have  been 
raised.  The  heaving  varied  from  i  in.  to  li  in.,  only  one  pier  having 
been  heaved  the  latter  amount.  But  at  this  street  no  pier  bottom 
was  less  than  5i  ft.  below  the  ground  surface.  It  is  certain  that 
frost  did  not  penetrate  to  that  depth.  It  is  unfortunate  that  test 
borings  for  depth  of  frost  penetration  were  not  made  at  both 
streets  in  order  that  more  exact  information  might  be  had  on  this 
point. 


42  The  Engineer  in  Field  and  Office 

Locomotive  Tows   Caissons  to  Place 

The  caissons  launched  for  the  bridge  at  Moncton,  N.  B.,  were 
quickly  and  easily  towed  to  place  by  a  locomotive  at  slack  tide  and 
moored  before  the  treacherous  currents  of  the  Petticodiac  River 
had  an  opportunity  to  carry  them  away. 

When  the  first  caisson  was  completed,  it  was  lowered  by  jacks  to 
sliding  ways  of  12  x  12-in.  timber  24  ft.  long.  Each  of  these  ways 
rested  on  one  of  the  four  main  ways,  which  were  spaced  on  14-ft. 
centers  under  the  caisson,  giving  an  overhang  of  13  ft.  at  each  end. 
The  main  ways,  which  were  braced  and  blocked  continuously,  had 
a  slope  of  about  1  to  9  and  were  run  into  the  ground  at  the  lower 
end  to  prevent  their  sliding.  The  struts  between  the  main  ways 
were  weighted  with  rails  to  keep  the  ways  from  floating  at  high 
water.  The  forward  ends  of  the  sliding  ways  were  also  weighted 
with  rails  to  sink  them  as  the  caisson  floated,  when  they  were  pulled 
clear  by  lead  ropes  attached  to  their  rear  ends. 

The  caisson  was  launched  one  hour  before  high  tide,  while  the 
current  was  still  running  in  slowly.  As  expected,  it  reached  the 
end  of  the  ways  before  floating,  giving  time  to  get  a  li-in.  steel 
towing  line  aboard  before  the  tide  rose  sufficiently  to  carry  it  clear 
of  the  ways. 

This  line  ran  through  snatch  blocks  on  scows  moored  at  pier  3 
and  at  the  site  of  the  caisson,  and  was  led  from  there  to  a  third 
sheave  in  line  with  a  siding  on  the  opposite  shore,  where  the  line 
was  attached  to  a  switch  engine.  As  the  caisson  floated,  the  loco- 
motive started  slowly,  pulling  it  over  to  the  first  scow  at  pier  3. 
The  shackle  pins  on  the  mooring  lines  of  this  scow  were  knocked  out 
and  scow  and  caisson  together  hauled  over  to  the  second  scow.  The 
latter,  moored  near  the  location  of  the  pier,  had  on  board  the  anchor 
lines  up  and  down  stream.  These  were  quickly  transferred  to  the 
caisson,  which  was  then  dropped  downstream  to  approximate  posi- 
tion. The  entire  operation  was  completed  before  the  outgoing  tide 
interfered. 

Bearing  Test  on  Confined  Wet  Sand 

A  concrete  slab-and-girder  mat,  with  the  wet  treacherous  sand 
underneath  confined  by  a  ring  of  interlocking  steel  sheet  piling, 
supports  the  new  boiler  house  and  coal-storage  plant  of  the  New 
York  Steam  Co.,  at  Burling  Slip  and  Water  St.,  in  downtown  New 
York  City.  The  load  of  the  boiler  room  averages  2.6  tons  per  sq.ft. 
of  the  entire  foundation ;  for  the  coal-plant  mat  the  load  is  5.4  tons. 
Before  the  Building  Department  would  permit  such  a  foundation  to 


Foundations 


43 


be  laid,  it  had  to  be  convinced  by  tests  of  the  safety  of  the  method. 
The  sketch  shows  how  the  loading  test  was  made  and  gives  the  settle- 
ment by  curves. 

The  test  arrangement  is  really  a  model  of  the  foundation  pro- 
posed. A  steel  sheet-pile  box  was  driven  to  a  depth  of  26  ft.  below 
curb  and  the  material  inside  excavated  to  a  depth  of  15  ft.  A 
concrete  slab  2£  ft.  thick  was  placed  on  the  sand  bottom  below 


Lead  in  Tons  per  Sq.ft. 


Loading  Test  for  Unusual  Foundation 

groundwater.  The  slab  was  loaded  with  pig  iron  to  give  a  maximum 
load  of  6  tons  per  sq.ft.,  and  readings  were  taken  on  the  four 
corners.  The  greatest  settlement  after  237  hours  was  0.061  ft., 
the  average  settlement  for  this  period  being  0.047  ft.  The  time 
curve  shows  that  there  was  no  settlement  between  load  applications. 


44 


The  Engineer  in  Field  and  Office 


New  Ideas  in  Designing  and  Building 
Bridges  and  Dams 

Clear  Form  of  Notes  for  Bridge  Stake-Out 

The  following  form  of  note  keeping  for  stake-outs  of  bridge 
bents  has  been  found  simple,  quickly  made  and  of  ready  reference 


"HIGH  BRIDGE"  5take-ou+ 


Mark.®  on  rock  near  left  stake  =  elev 


B.M.*2  •       1095.49     1 127.82  *bot.  cap 
6.5.      •       __416./»!0954bFtqs. 
H.  I.      *       1099.65   3/3241 '32'-05*Heioh< 
r°d     -  4.44  \     3  60  lt 

rELFootinqs «    l095.4|-qdd7.'QO  10.60-10-07^ 

4- 
Offset  stakes®  I4'-07^" 


Bent   @Sta280t9fl5 


Mark,  ®  top  of  left  stake=elev^ 


J.PT.U/ 
Instrument  "Transit       AJY)  Z7"'7 


B.M*4    1113.55        1127.64-  bah  cap. 
B.S   =       0.33      r  1  109.03  =  F 


^rllU9.UJ  =  rtqs. 

j  9JI6.6I  'iS'-OTl^igM 

r  add  7.00  =9.07=  9'-Ol" 


"I  '•     1113.86 

levFtqs->H09.03yadd  7.00 -9.07- 9'-QJ 

add 
Offset  stakes  © 


Record  Bridge  Stake-Out  Operations  in  This  Manner 

on  the  job.  If  the  bridge  is  on  a  grade,  it  is  necessary  to  have 
available,  preferably  in  the  same  notebook  with  the  stake-out  records, 
the  information  indicated  in  the  accompanying  table. 

DATA    ON     "HIGH     BRIDGE" 


Station 

280  +  80.5 

280  +  98.5 

281  +  16.5 


Bent  No. 

12 
13 
14 


Grade  (1%) 
Floor  Surface  Bottom  of  Cap 


1129.82 
1129.64 
1129.46 


1127.82 
1127.64 
1127.46 


With  the  above  data  and  benchmark  levels  readily  accessible, 
the  staking  out  of  the  bridge  bents  is  undertaken,  and  the  operations 
so  performed  are  recorded  in  the  manner  suggested  by  the  illustra- 
tion of  a  typical  field  notebook  opening. 


Bridges  and  Dams  45 

Temporary  Hinges  for  Concrete  Arches 

The  common  assumption  that,  with  an  arch  curve  laid  out  to 
conform  to  the  dead-load  equilibrium  curve  the  dead-load  produces 
no  bending  moments  in  the  arch,  is  materially  in  error.  This  error 
arises  from  the  arch  shortening  produced  by  the  dead-load  compres- 
sive  stresses  and  is  similar  to  a  fall  in  temperature;  it  results  in  a 
reduction  of  the  horizontal  thrust,  with  a  consequent  divergence  of 
the  true  pressure  line  from  the  assumed  arch  axis.  The  pressure 
line  then  passes  above  the  axis  at  the  crown  and  below  the  axis 
at  the  springing,  thereby  increasing  the  compression  in  the  outer 
fibers  at  the  crown  and  in  the  inner  fibers  at  the  springing. 

The  magnitude  of  the  foregoing  error  depends  upon  the  propor- 
tions of  the  arch.  It  may  be  neglected  in  arches  having  a  rise 
greater  than  one-fourth  of  the  span ;  but  in  flatter  arches  it  becomes 
increasingly  serious.  From  some  designs  that  have  been  worked  out, 
in  which  the  depth  of  rib  was  uniformly  3%  of  the  span  length, 
it  appears  that  the  addition  to  the  dead-load  stresses  on  account  of 
rib-shortening  may  attain  considerable  magnitude,  especially  in  the 
flatter  arches. 

A  method  of  avoiding  these  additional  stresses  is  to  provide 
hinges  at  the  crown  and  springing  during  the  erection  of  the  arch. 
Temporary  hinges  were  employed  by  the  late  George  S.  Morison  in 
the  construction  of  masonry  arches;  they  have  also  been  used  in  a 
number  of  European  bridges.  These  hinges  should  be  closed  by 
pouring  concrete  into  the  joints  only  after  the  full  dead-load  is  on 
the  structure  and  the  shortening  and  shrinkage  changes  have  taken 
place.  By  selecting  the  temperature  for  closing  the  hinges,  the  range 
and  effect  of  the  subsequent  variation  may  be  minimized. 

The  above  advantages  of  the  three-hinged  construction  apply 
mainly  to  the  conditions  during  erection.  For  the  finished  structure, 
a  hingeless  type  is  to  be  preferred  on  account  of  the  greater  rigidity 
and  the  greater  security  against  crown  settlement.  Temporary 
hinges  eliminate  the  shrinkage  stresses  without  involving  the 
difficulty  in  the  construction  of  bulkheads  caused  by  interference 
with  the  steel  in  the  case  of  reinforced  construction. 

Circular  Curve  for  Arch  Design 

In  laying  out  an  arch  curve  for  the  first  trial  design,  a  simple 
circular  curve  is  ordinarily  satisfactory.  With  this  curve  drawn, 
the  weights  of  the  arch  segments  and  superimposed  filling  are  figured 
and  the  resulting  equilibrium  curve  constructed.  With  this  pressure 
line  as  a  new  arch  curve,  the  deadloads  may  be  revised  and  a  second 


46  The  Engineer  in  Field  and  Office 

equilibrium  curve  drawn ;  as  a  rule,  however,  the  first  curve  may  be 
retained  without  the  revision  of  a  second  trial. 

For  ordinary  concrete  arches  with  earth-filling  up  to  a  level  line, 
the  ideal  arch  curve  will  be  found  slightly  higher  at  the  haunches 
than  a  simple  circular  curve.  The  following  table  gives  the  amount 
of  this  deviation,  as  found  from  actual  designs,  for  different  rise- 
ratios  : 

Deviation   from  Circular  Curve 

Ratio  of  Rise  at  Haunches,  in  Per  Cent. 

to  Span  of  Rise 

0.25  4.3 

0.20  4.2 

0.15  3.7 

0.10  35 

0.07  3.1 

In  the  flatter  arches,  the  deviation  from  a  circular  curve  is  barely 
noticeable. 

Theoretically,  the  ideal  arch  curve  is  the  equilibrium  curve  for 
the  dead-load  plus  one-half  of  the  live-load  covering  the  full  span. 
This  curve  would  be  the  exact  mean  of  the  two  extreme  curves 
obtainable  by  placing  the  live-load  alternately  on  the  two  halves 
of  the  span.  In  practice,  however,  on  account  of  the  usual  small 
ratio  of  live-  to  dead-load,  there  is  no  material  difference  in  using 
the  equilibrium  curve  for  dead-load  alone. 

Approximate  Methods  for  Arch  Design 

The  elastic  theory  when  applied  to  arches  with  fixed  ends  is  not 
only  time-consuming,  but  is  essentially  a  method  of  analysis  and  not 
directly  of  design.  Hence  there  is  a  real  need  for  satisfactory 
formulas  or  methods  for  determining  approximately  the  crown 
thickness  and  the  proper  form  of  the  arch  ring.  It  is  necessary 
in  order  to  determine  the  stresses  to  assume  the  dimensions  of  the 
arch  rib.  Experience  must  be  the  main  guide  in  this  primary 
assumption,  and  the  designer  has  two  classes  of  aids: 

1.  Emperical  formulas,  which  are  crystallized  expressions  of  past 
experience ; 

2.  Approximate  methods,  by  which  crown  thrusts  and  lines  of 
pressure  may  be  determined. 

Formulas  of  the  first  class  are  the  modern  representatives  of 
the  experimental  proportions  which  probably  guided  the  ancient 
arch  builders.  Methods  of  the  second  class  are  an  outgrowth  of 
the  line  of  pressure  theories  developed  for  voussoir  arches,  and 
are  an  improvement  over  class  1,  principally  in  that  a  greater  range 
of  conditions  can  be  considered,  and  that  more  particulars  of  the 
form  of  the  arch  can  be  determined  by  their  use. 


Bridges  and  Dams  47 

Joseph  P.  Schwada  has  developed  formulas  for  the  thrust  T  and 
the  depth  d  at  the  crown  in  terms  of  a  coefficient  K  representing 
the  ratio  between  the  average  crown  stress  and  the  maximum  stress 
in  the  arch.  The  following  equation  has  been  derived  for  the  thrust, 
based  upon  the  assumptions  used  by  Mr.  Schwada,  but  using  the 
general  formulas  derived  by  C.  Tourtay  in  1902.  In  Mr.  Schwada's 
notation  : 


This  equation  gives  slightly  lower  values  than  Mr.  Schwada's 
equation,  all  terms  being  identical  except  those  in  the  parenthesis 
containing  R  and  d.  The  depth  at  crown  is 

T 

d  = 


144/Jf 

Mr.  Schwada  presents  a  valuable  series  of  diagrams  and  tables 
for  the  value  of  the  coefficient  K,  and  for  the  solution  of  his 
equations. 

The  process  of  the  design  of  an  arch  ring  is  then  as  follows : 

1.  Tabulate  the  general  conditions  which  can  be  at  once  deter- 
mined  or  assumed,   and   the   known   factors   such   as   span,   rise, 
loads,  etc. 

2.  Make  a  rough  assumption  of  the  crown  and  springing  line 
thickness  (possibly  using  a  formula  of  class  1). 

3.  Compute  the  value  of  thrust  T,  and  if  necessary  correct  the 
assumed  crown  thickness. 

4.  Construct  a  line  of  pressure  with  horizontal  thrust    (pole 
distance  in  the  force  polygon)  equal  to  T. 

5.  Choose  a  value  for  K  which  will  suit  the  type,  the  rise,  and 
the  span  of  the  arch,  and  compute  the  value  of  the  crown  thickness  d. 

6.  Choose  a  curve  for  the  arch  axis  which  will  fit  the  line  of 
pressure  constructed  as  in  4. 

7.  Vary  the  thickness  of  the  arch  and  place  the  reinforcement 
in  accordance  with  the  thrusts  shown  in  the  force  diagram,  but 
making   proper   allowance   for   the   effects   of   moving   loads   and 
temperature. 

8.  Analyze  the  arch  thus  determined  by  the  elastic  method. 

It  will  be  found  that  a  very  close  approximation  to  the  best 
design  is  determined  by  the  first  seven  steps,  and  only  minor  changes 
may  be  expected  from  the  full  elastic  analysis,  while  the  labor  is 
far  less  than  a  preliminary  analysis  by  the  elastic  method. 


48 


The  Engineer  in  Field  and  Office 


Culvert  Pipe  Used  as  Basis  for  Floor  System  to  Bridges 

A  reversion  to  an  old  system  of  highway  bridge  floor,  with  some 
modern  variations,  is  seen  in  the  use  of  corrugated  iron  culvert 


Underside  of  Colorado  Bridge  Floor  Where  Culvert  Half 
Rounds  Are  Used  as  Forms 

pipe  forming  the  basis  for  concrete  arch  floor  spans.     In  the  old 
designs  light  gage  corrugated  steel  in  the  new  type  half  sections 


Concrete  Floor  of  Ohio  Bridge  To  Be  Placed  on  Culvert 
Sections  as  Forms 

of  heavy-gage  culvert  iron  is  used,  with  additional  reinforcement 
of  the  concrete  floor  against  expansion. 


Bridges  and  Dams 


49 


One  view  shows  such  a  floor  as  installed  on  a  through-truss 
bridge  in  Hamilton  County,  Ohio.  For  this  bridge  the  culvert  forms 
span  between  the  bottom  flanges  of  I-beam  stringers  which  are 
framed  into  floor-beams.  The  other  view  shows  the  under  side  of 
the  floor  of  a  deck-girder  bridge  at  Boulder,  Colo.  Here  the  main 
girders,  41-ft.  span,  are  of  reinforced  concrete  and  the  floor,  a 
concrete  slab  reinforced  against  expansion  with  l-in.  rounds  on 
10-in.  centers  in  both  directions,  is  poured  on  half-culvert  sections 
spanning  steel  24-in.  I-beams  which  are  spaced  4  ft.  apart  and 
placed  parallel  to  the  main  girders  and  span  between  the  abutments. 
In  this  bridge  the  I-beam  stringers  are  stiffened  by  cross-braces 
of  steel  bars,  as  shown. 

Bridge  Erected  With  A-Frame 

An  example  of  the  solution  of  a  difficult  erection  problem  through 
taking  advantage  of  the  exceptional  natural  conditions  is  seen  in 
the  methods  adopted  in  the  case  of  the  Pool  Point  Bridge  on  the 
Elkhorn  extension  for  the  Carolina,  Clinchfield  &  Ohio  Railway.  This 
bridge  crosses  a  deep  basin  in  which  there  is  always  from  50  to 


Center  Support  Was  Provided  for  Cantilever  Erection 

90  ft.  of  water.  The  stream  is  of  torrential  character,  and  above 
the  site  of  the  bridge  is  a  splash  dam  which  at  times  discharges 
large  numbers  of  logs  which  would  carry  out  any  ordinary  falsework. 
These  special  conditions  made  it  impracticable  to  use  falsework 
of  the  usual  type.  The  character  of  the  rocky  side  walls  suggested 
the  use  of  an  A-frame  or  arch  type  of  center  support  and  cantilever 
erection  from  the  north  shore  for  the  270-ft.  main  truss  span.  This 
design  was  therefore  made  of  the  riveted  type,  with  provision  for 
compression  in  the  lower  chords  and  proper  sections  throughout 
for  cantilever  erection  beyond  the  center-panel  point.  The  A-frame 
legs  were  made  of  derrick  booms. 


50 The  Engineer  in  Field  and  Office 

The  main  truss  span  of  nine  30-ft.  panels,  270  ft.  long,  flanked 
on  the  north  by  a  50-ft.  girder  span  and  on  the  south  by  a  70-ft. 
girder  span  is  composed  of  two  trusses  spaced  19  ft.  apart  on  centers. 
The  main  span  weighs  613  tons,  and  the  order  of  procedure  in 
erection  was  as  follows: 

The  end  post  and  50-ft.  plate  girder  span  having  been  erected 
by  the  derrick  car,  the  car  could  be  advanced  and  the  first  panel 
placed  with  a  temporary  wooden  bent  at  panel  point  Lj.  The  car  was 
then  advanced  and  the  A-frame  legs  were  placed  on  the  north  side 
and  held  in  position  by  guys.  Following  this,  lines  having  been 
passed  to  the  other  bank,  the  south  legs  of  the  A-frame  were  swung. 

The  shore  ends  of  the  A-frame  had  cast-steel  bolsters  supported 
on  concrete  skewbacks  and  the  tops  were  provided  with  cast-steel 
shoes  for  supporting  the  truss.  The  A-frame  being  in  place,  the 
remaining  panels  up  to  the  center  were  erected,  the  splices  being 
located  as  shown  on  the  diagram,  and  the  center  panel  point  blocked 
up  on  top  of  the  A-frame.  From  this  point  cantilever  erection 
proceeded  regularly  panel  by  panel  until  the  shoe  at  the  south  end 
had  been  placed. 

The  deflection  of  the  cantilever  end  was  about  8  in.,  and  care 
had  been  taken  to  block  the  center  high  enough  to  bring  the  south 
end  about  a  foot  high,  allowing  for  this  deflection.  Jacks  were  then 
applied  and  this  south  end  lifted  until  the  span  was  free  at  the 
center.  The  A-frame  was  removed  and  the  span  lowered  to  the 
masonry. 

Radial   Bracing   for   Large   Cofferdam 

In  constructing  a  steel  sheet-pile  cofferdam  46  ft.  in  diameter 
for  the  Pennsylvania  R.R.  it  seemed  desirable  to  use  a  quantity  of 
8  x  16-in.  18-ft.  timber,  which  was  on  hand,  for  bracing.  As  the 
distance  across  the  cofferdam  was  more  than  twice  the  length  of 
the  timber,  a  wood  pile  was  driven  in  the  center  of  the  cofferdam 
before  excavating;  and  a  "hub"  supported  by  this  pile  was 
constructed.  Excavation  has  been  carried  18  ft.  below  water  level, 
and  two  sets  of  waling  and  struts  have  been  placed  in  this  manner. 
The  method  has  been  very  successful. 

Forms  Have  Sliding  Cantilevered  Studding 

Cantilevered  vertical  studding  which  does  not  have  to  be  taken 
down  to  set  the  next  lift  of  forms  is  used  to  support  the  forms  for 
La  Loutre  dam,  being  built  on  the  upper  St.  Maurice  River.  By  the 
use  of  such  supports  the  interior  spaces  where  concrete  is  being 


Bridges  and  Dams  51 

deposited  are  kept  clear  of  all  tie  rods.  Two  pieces  of  timber  on 
edge  are  held  parallel  and  1  in.  apart,  being  double  bolted  through 
a  space  block  at  the  upper  end.  This  arrangement  gives  a  slot  the 
whole  length  of  the  support,  so  that  it  can  be  slid  vertically  upward 
for  another  lift  of  concrete.  In  this  respect  the  scheme  differs  from 
previous  forms  of  same  type. 

The  holding  bolts  are  tightened  when  the  form  and  support  are 
in  place  for  proper  alignment.  If  there  is  any  overhanging,  the 
heel  or  lower  end  of  the  support  is  blocked  outward.  Form  framing 
here  is  horizontal  and  lagging  is  vertical. 

Holding  bolts  1  in.  in  diameter  are  spaced  at  2-ft.  intervals.  The 
bolts  are  wrapped  in  a  sleeve  made  of  paper  which  has  been  dipped 
in  tar  and  dried.  At  the  inner  end  is  a  3  x  3  x  T5F-in.  plate.  Very 
little  difficulty  has  been  found  in  screwing  the  bolts  out.  Large 
square  washers  at  the  end  span  both  timbers  of  the  support. 

Automatic  Flood  Gates  for  17-ft.  Dam 

The  17-ft.  concrete  dam  for  a  hydro-electric  plant  on  the  Cedar 
River  at  Nashua,  Iowa,  is  equipped  with  a  number  of  automatic  flood 
gates  each  46  ft.  long  and  holding  back  a  maximum  of  7  ft.  of  water. 
The  installation  of  the  flood  gate  is  worthy  of  comment,  because 
this  particular  type  is  new  to  this  country.  It  was  imported  from 
Switzerland  and  service  has  already  proved  its  value.  It  is  simply 
a  walking-beam  with  a  gate  hung  at  one  end  and  a  concrete 
counterweight  hung  at  the  other.  The  gate  is  hinged  at  the  bottom. 
When  the  water  rises  above  the  required  elevation,  the  gate  turns 
down,  which  in  turn  raises  the  counterweight.  The  higher  the 
water  the  farther  it  opens  the  gate.  When  the  gate  opens,  the 
leverage  between  the  counterweight  and  fulcrum  increases  and  that 
between  the  gate  hinges  and  fulcrum  decreases,  thereby  overcoming 
the  increased  weight  of  water  at  every  stage  of  gate  opening. 
Gravity  and  constantly  shifting  leverage  are  its  features.  The  gate 
is  of  steel  and  was  entirely  fabricated  and  set  before  grouting  in. 

Creosoted  plank  was  used  for  decking,  well  bolted  on.  Leaking 
around  the  ends  was  prevented  by  a  leather  bearing  on  the  concrete. 
A  leather  bearing  on  a  curved  plate  prevented  leakage  over  the 
hinge  where  the  gate  fastened  to  the  rollway.  The  counterweight 
was  formed  and  poured  in  place,  being  shored  up  from  the  crest  of 
the  dam. 

Concrete  Closing  Slabs  Slide  to  Place 

On  the  construction  of  the  dam  at  the  new  hydro-electric  plant 
at  Hiram,  Me.,  on  the  Saco  River,  water  was  allowed  to  flow  through 


The  Engineer  in  Field  and  Office 


the  dam  during  the  main  building  period,  three  openings  being  left 
in  the  lower  part  of  the  deck.  Closure  was  then  accomplished  by 
three  reinforced  concrete  gates  which  were  cast  upon  the  deck  of 
the  dam  as  shown  and  each  held  in  position  by  a  wire  rope  attached 


/7&  close  Ga+e 
saw  Loo  here 


^•issyS?:\ 

#'••&  6ATE''*    :  \  $>>;6ATE  ' 

p^^iM^I^;- 

&.4^fiM^*^*4*i'*A« 


S  e  c  -t-  i  o  n 


Sec-Hon  through  Ga-f-es 


Ups-t-ream       Eleva-fion 

Slabs  Slid  Down  Deck  of  Dam  on  Greased  Tarpaper 
To  Make  Closure 

to  log  anchored  under  the  opposite  wall  of  the  dam  by  a  second  rope 
and  hook.  Each  closure  gate  was  reinforced  both  ways  with  l-in. 
square  rods  spaced  4  in.  on  centers  and  was  provided  with  a  U-bolt 
by  which  the  wire  attachment  was  made.  To  prevent  adhesion 
between  the  closure  slabs  and  the  deck  of  the  dam,  two  layers  of 
single-ply  roofing  paper,  greased  between  layers,  formed  the  base 
upon  which  the  concrete  was  poured.  The  closure  gates  were  about 
16  ft.  high,  18  in.  thick  and  15  ft.  wide,  sliding  downward  between 
guides  composed  of  4-in.  tees  flanked  by  4-in.  by  i-in.  plate  on  each 
side.  By  sawing  off  the  log  above  each  gate  on  the  top  of  the 
dam  the  slab  was  released  and  slid  into  place  seating  against  a 
concrete  recess  at  the  bottom  of  the  deck,  as  shown  in  the  cross- 
section. 


Bridges  and  Dams 


Slipping  Bridge  Abutment  Saved 

A  casual  inspection  of  the  100-ft.  steel  highway  bridge  which 
was  built  some  time  ago  without  engineering  supervision  showed 
that  the  anchor  bolts  were  bent  and  the  shoes  were  pressed  tightly 
against  them.  There  was  no  information  available  as  to  the  exact 
location  of  the  abutment  or  as  to  the  batter  of  the  faces,  but  it  was 
very  easily  seen  that  one  of  the  abutments  had  moved.  An 
investigation  indicated  that  while  one  abutment  rested  on  hardpan 
or  rock,  the  other — which  is  about  18  ft.  high  above  water  level 
and  of  unknown  depth  below — probably  rests  on  a  fine  sandy  loam. 
The  stream  channel  shifting  had  eroded  this  deeply. 

To  prevent  further  erosion,  two  lines  of  piles  were  driven  near 
the  toe  of  the  slope  and  the  whole  slope  covered  with  a  heavy  riprap 
of  stone.  Holes  were  drilled  through  the  abutment  near  the 
juncture  of  the  wings  and  face,  and  14-in.  rods,  34  ft.  long,  were 


Abutment  Retained  by  Concrete-Incased  Rods  Passing 
Through  Concrete  Deadmen 

placed  in  trenches  running  back  along  the  roadway.  These  rods 
were  incased  in  concrete  for  their  entire  length  and  anchored  to 
concrete  deadmen  at  the  end. 

To  further  strengthen  the  abutment,  a  narrow  trench  was  dug 
along  its  back  and  filled  with  concrete — the  extra  width  providing 


54 


The  Engineer  in  Field  and  Office 


sufficient  breadth  to  receive  the  bearing  when  it  was  replaced  in  its 
proper  position. 

When  the  concrete  at  this  point  was  hardened  sufficiently,  the 
nuts  were  tightened  on  the  tie-rods,  a  new  anchor  bolt  hole  drilled 
and  the  bolt  grouted  in.  To  lift  the  bridge  while  widening  the 
seat  beams,  struts  made  of  pine  logs  flattened  on  two  sides  were 
attached  at  the  first  panel  points,  as  is  indicated  in  the  line  drawings. 
A  beam  rested  on  top  of  these  struts  and  passed  under  the  top  chord. 
The  bottom  chords,  stiffened  by  means  of  4x6  timbers  inserted 
between  the  floor-beams,  completed  the  provisions  against  reversed 
stresses. 

Arches  Destroyed  by  War  Replaced  Quickly 

The  exigencies  of  battle  in  the  north  of  France  have  required 
the  rapid  and  stable  reconstruction  of  a  number  of  masonry  arch 
bridges  that  had  been  more  or  less  completely  destroyed  by  the 
German  or  by  the  Allied  forces.  These  bridges  are  generally  in 
an  area  where  timber  and  cut  stone  are  scarce,  and  their 
reconstruction  must  be  done  rapidly  without  the  aid  of  the  needed 
quota  of  skilled  artisans.  To  meet  these  conditions,  concrete  arches 
placed  without  the  use  of  falsework  have  been  successfully 
employed  in  a  number  of  cases. 


Method  of  toying  Up  Arch 


Fig.  1.  Restoring  Arches  in  Destroyed  Stone  Bridges  in  Battle 
Area  of  France 

Cement  can  more  readily  be  brought  forward  than  any  other 
structural  material,  and  sand  and  gravel  are  local  products,  so  that 
concrete,  which  can  be  made  by  unskilled  labor,  is  doubly  effective 
for  such  work.  A  novel  feature  of  the  reconstruction  is  the  use 
of  old  iron  and  a  minimum  of  timber  for  arch  centers,  which  can 
be  readily  erected,  thus  saving  time  and  labor. 


Bridges  and  Dams 


55 


The  first  operation  in  the  reconstruction  of  one  bridge  was  to 
build  the  light  timber  framework  carrying  the  footway  and  erect 
thereon  the  towers  for  a  construction  cableway.  From  this  cableway 
a  series  of  centering  ribs  made  up  of  old  steel  rails  was  placed. 
These  rails,  which  were  found  in  the  neighborhood,  weighed  60  Ib. 
to  the  yard.  They  were  cold  bent  to  the  proper  curve,  in  two 
sections  and  spaced  20  in.  c.  to  c.  clear  across  the  arch.  At  the 
abutment  they  were  bolted  to  a  bedplate  that  was  held  by  a  hook 
bolt  driven  into  the  masonry.  These  curved  rails  were  used  as  the 
basis  of  a  thin  concrete  arch  that  in  itself  served  as  the  center  for 
the  main  arch.  This  procedure  was  adopted  rather  than  placing 
the  main  arch  immediately  upon  falsework  hung  from  the  steel 
ribs  themselves,  because  the  rails  were  not  sufficiently  strong  to 
act  as  centers. 


Cross-Section  of  Falsework  Center 
60- Ib.  Rail 


Bearing 
Of  Kail 

.  a+ 
Abutment 


Elevation  of 

Falsework  Center 


Fig.  2.  Details  of  the  Steel-Rail  Arch  Centering  Used  on 
Meurthe  River  Bridge 

The  centering  consisted  merely  of  timber  joists  and  a  floor. 
This  concreting  was  done  in  two  parts,  a  1:2:4  concrete  was 
placed  for  its  uniform  thickness  of  10  in.  from  abutment  to 
abutment,  and  for  the  full  width.  On  this  a  concrete  arch  rib  and 
two  abutment  sections  were  first  placed  and  the  intermediate 
sections  last.  The  concreting  of  this  shallow  section  could  be 
done  in  one  morning.  Ten  days  was  allowed  for  this  concrete  to 
set.  Meanwhile  the  top  of  the  rib  was  laid  off  in  19  voussoirs,  and 
a  vertical  dividing  wall  was  erected  across  the  arch  at  each  voussoir 
division  line.  This  dividing  wall  was  made  of  a  wire  mesh,  large 


56  The  Engineer  in  Field  and  Office 

enough  to  hold  the  aggregate,  fastened  to  f-in.  and  f-in.  vertical 
rods  tied  in  at  the  bottom  to  hook  bolts  that  had  been  left  emerging 
from  the  centering  concrete.  These  frameworks  having  been 
placed  during  the  10  days  allowed  for  the  setting  of  the  centers, 
concreting  was  carried  on  across  the  arch  rib  in  the  voussoirs  so 
laid  out,  placing  them  across  the  bridge  so  as  to  impose  the  least 
eccentric  loading  on  the  centering  arch.  The  progress  of  voussoir 
deposition  is  shown.  All  this  concreting  for  one  6-ft.  arch  could 
be  done  in  two  10-hour  days. 

After  the  main  arch  rib  has  achieved  a  sufficient  set,  the 
centering  arch  can  be  removed,  although  this  is  not  necessary. 
Meanwhile,  the  superstructure  of  the  arch  can  be  erected  in  a 
continuous  process  following  the  construction  of  the  main  arch 
rib,  and  the  roadway  put  into  service  in  a  minimum  of  time. 

Top  Forms  in  Arch  Concreting 

Top  forms  were  considered  necessary  on  the  new  Chesapeake  & 
Ohio  Northwestern  Ry.  work  at  Sciotoville,  Ohio.  It  has  long  been 
usual  in  concrete  bridgework  to  omit  top  forms  near  the  crown  of 
the  arch  where  the  slope  is  very  small,  but  of  late  it  has  become 
rather  common  practice  to  omit  these  forms  far  down  the  arch  rib 
slope  and  to  attempt  to  screed  the  top  surface  to  line.  Concrete 
so  placed  is  apt  to  pile  up,  causing  an  excess  of  arch-ring  depth  at 
the  bottom  of  the  section  poured  and  a  thinning  of  the  ring  near 
the  crown.  Therefore  a  top  form  for  the  haunch  section  of  the 
arch  ring,  which  extends  from  the  springing  line  to  a  crown  section 
placed  in  advance  about  3  ft.  on  either  side  of  the  crown,  was  used 
on  this  bridge. 

A  Small  Bobtail  Draw 

In  building  a  swingbridge  across  a  neck  of  Lake  Lucerne  at 
Stansstad,  Switzerland,  for  22  m.  clear  opening,  the  engineers  for 
the  Canton  Nidwalden  adopted  the  bobtail  swing  type  but  detailed 
it  in  such  manner  as  to  make  substantially  a  single-leaf  swing.  The 
short  arm  ends  just  beyond  the  turntable,  so  far  as  the  bridge  floor 
is  concerned.  It  extends  out  under  the  approach  floor,  however, 
as  counterweight  for  the  long  arm.  The  approach  deck  over  this 
counterweight  has  supports  at  one  side  only,  the  other  side  being 
left  clear  to  allow  the  counterweight  to  swing  out.  The  result  of 
this  arrangement  is  that  rocking  action  due  to  live-load  on  the 
short  arm  is  nearly  eliminated,  making  it  possible  to  dispense  with 
wedging  Or  tight  latching  at  the  outer  end  of  the  long  arm,  as  well 


Municipal  Engineering 


57 


as  with  bearings  under  the  short  arm.  The  operating  machinery 
is  thereby  simplified,  and  the  required  power  reduced,  which  (the 
bridge  being  hand-operated)  means  that  the  time  required  for 
opening  and  closing  is  reduced.  The  end  of  the  long  arm  has  one 
lower  and  two  upper  track-wheel  supports,  and  these  enter  between 
tracks  inclined  slightly  upward,  as  the  bridge  closes.  There  are 
also  two  flat  bearings,  one  under  each  girder,  but  they  are  adjusted 
to  be  barely  in  contact  when  no  live-load  or  wind  is  acting.  The 
turntable  is  center-bearing  and  has  two  side  wheels  and  two  at  the 
quarter-points  nearest  the  channel. 

Field  Determination  of  Bridge  Skew 

In  reconnoissance  work  for  ordinary  highway  bridges  no  great 
accuracy  is  required  in  determining  the  skew;  even  a  variation  of 
5°  being  seldom  important.  A  method  of  determining  this  skew  in 
the  field  is  to  take  an  ordinary  6-ft.  rule,  hinged  about  its  3-ft. 
joint,  place  one  arm  in  the  line  of  the  road  and  the  other  arm  in 
the  line  of  the  stream;  the  distance  between  the  two  ends  is  the 
chord  of  the  angle  of  skew  of  the  bridge.  The  following  is  a  table 
by  which  the  angle  can  be  determined : 

Radius  equals  36  in. 


Chord 

18  in. 

20  in. 

22  in. 

24  in. 

26  in. 

28  in. 

30  in. 

32  in. 

34  in. 


Angle 
29°  00 
32°  20 
35 
39 


42' 
45< 
49C 
52C 
56' 


40' 
00' 
20' 
40' 
20' 
40' 
20' 


Chord 

36  in. 

38  in. 

40  in. 

42  in. 

44  in. 

46  in. 

48  in. 

50  in. 


Angle 
60°  00' 
63°  40' 
20' 
20' 
20' 
20' 
40' 


67° 
71° 
75 

79 
83 


88°  00' 


Intermediate  angles  can  easily  be  interpolated. 


Helps  for  Municipal  and  County  Engineers 

Tile  Drains  Under  Curbs  in  Syracuse 

The  accompanying  sketches  show  how  the  City  of  Syracuse 
drains  all  pavement  foundations.  The  curbing  is  set  in  a  block 
of  concrete  18  in.  wide  and  12  in.  deep.  Under  this  block  of  concrete 
is  18  in.  of  cobblestone  filling,  along  the  edge  of  which  is  laid  a  3-in. 
tile  drain  which  empties  into  the  sewer  catch-basins.  Wherever 
there  are  street  railway  tracks  a  5  x  16-in.  Medina  curb  or  header 
is  placed  against  the  ends  of  the  ties  and  a  similar  construction, 
as  shown  in  the  right-hand  sketch,  is  used.  It  is  said  that  in  the 


58 


The  Engineer  in  Field  and  Office 


spring,  when  the  frost  is  coming  out  of  the  ground,  these  drains 
empty  a  continuous  flow  into  the  sewer  catch-basins,  and  there  is 


MZDINA  CURB 


Fbrvemen-f- 


3"Tile- 


Standard  Drainage  Details  for  Concrete  Curb    (Left)   and 
Special  Curb  at  Railroad  Crossing  (Right) 

no  question  but  that  they  save  many  pavement  troubles.  They  are 
used  in  all  kinds  of  subsoil  and  beyond  the  price  of  the  tile  they 
add  practically  nothing  to  the  cost  of  the  pavement. 

Types  of  Drinking  Fountains  Tested 

Tests  of  77  drinking  fountains  of  15  different  types  showed 
that  due  to  improper  design  all  were  possible  sources  of  infection 
of  the  users.  No  less  than  80%  of  the  fountains  and  the  water 
from  11%  of  them  contained  streptococci,  although  none  were 


These  Fifteen  Types  Showed  80%  o/  the  Fountains  and  11% 
oj  the  Water  Samples  Infected 

found  in  the  water  supplied  to  the   18  buildings  in  which  the 
fountains  were  located. 

The  infection  was  due  to  contact  between  the  lips  of  users  and 
the  structure  of  the  fountains,  or  to  water  falling  back  from  lips 


Municipal  Engineering 


59 


to  fountains,  owing  to  vertical  discharge  of  the  jet.  To  keep  lips 
away  from  the  fountain  structure  and  water  from  falling  back  on 
it,  and  to  prevent  water  from  being  retained  in  fountains  with 


Three  Tests  of  This  Protected  Drinking  Fountain  Showed 
No  Streptococci  Infection 

cup-  or  ring-shaped  depressions,  the  fountain  shown  herewith  was 
designed.  Three  bacterial  tests  showed  no  streptococci  on  either 
the  fountain  or  the  water  discharged  from  it. 


When  To  Haul,  When  To  Waste  and  Borrow 

A  simple  formula  by  which  to  calculate  the  economical  length 
of  haul  beyond  which  it  is  preferable  to  waste  and  borrow  may  be 
developed  as  follows: 

Take  two  adjacent  sections,  one  in  cut,  the  other  in  fill,  and 
each  containing  the  same  volume  of  material  V,  measured  in 
excavation  in  both  cases.  Under  this  condition  the  material  taken 
from  the  cut  will  just  make  the  fill,  and  therefore,  provided  the  haul 
from  cut  to  fill  is  of  a  certain  length,  the  total  cost  of  grading  the 
two  sections,  with  all  the  material  from  cut  used  in  fill,  will  be  the 
same  as  by  the  system  of  borrow  and  waste.  These  two  conditions 
may  be  expressed  by  the  equation 

V(a  +  cte/100)  =  V(a  +  6)  +  Vc 

in  which  a  equals  cost  of  excavating  and  loading,  in  cut,  per  cubic 
yard;  6,  cost  of  hauling  and  dumping  wasted  material,  per  cubic 
yard;  c,  cost  of  borrow  and  fill,  not  rolled,  per  cubic  yard;  d,  cost 
of  hauling  and  dumping  material  taken  from  cut  to  fill,  per  cubic 
yard  hauled,  and  x  length  of  haul,  center  of  gravity  of  cut  to  center 
of  gravity  of  fill,  in  feet. 


60 


The  Engineer  in  Field  and  Office 


Eliminating  V  and  a  from  the  equation  and  reducing, 


=          c 
whence 

x  =  100(&  +  c)/d 

Very  likely  d  will  be  found  practically  constant  for  the  entire 
job,  but  b  and  c  will  need  to  be  estimated  separately  for  each  cut 
and  fill,  and  will  no  doubt  show  considerable  variation. 

Irregular  Street  Intersection  Area  Calculations 

It  is  almost  always  necessary  to  compute  the  areas  of  some 
very  irregular  street  intersections  at  the  time  of  their  improvement. 
Unless  some  planning  is  done  beforehand,  the  proper  measurements, 
which  will  result  in  a  determination  of  the  area  with  any  degree 
of  precision,  are  not  made  in  the  field.  The  accompanying  diagram 
of  a  hypothetical  intersection  serves  to  illustrate  the  use  of  a  special 


Computations  of  Areas  of  This  Nature  Simplified 

curve  by  which  the  calculations  are  simplified,  and  its  employment 
will  make  the  fieldwork  as  simple  as  possible.  Only  a  very  brief 
explanation  will  make  clear  the  proper  procedure  to  follow  in  the 
field. 

Let  us  assume  that  the  areas  of  H,  I  and  /  are  desired.  While, 
of  course,  it  is  not  exactly  true  that  the  curves  at  the  intersection 
are  always  arcs  of  circles,  they  may  be  considered  so  for  practical 


Municipal  Engineering 


61 


purposes,  and  very  close  results  will  be  reached  if  proper  averages 
are  taken. 

To  compute  these  areas,  the  average  radius  and  the  internal 
angle  must  be  determined.     Since  the  ratio  of  T  to  E  is  the  same 


\ 


20 


60        90 


30         40          50         60         70 
Values  of  ^  in   Degrees 

Enter  This  Curve  with  Average  of  Linear  Measurement 
To  Get  Average  Angle 

as  that  of  C  to  2M,  as  may  be  seen  from  the  small  diagram  given 
with  the  curve,  the  one  curve  is  all  that  is  necessary.  To  determine, 
for  instance,  the  area  marked  J,  the  procedure  would  be  as  follows : 

l=ff°r2-91 

C       23.8 


With  this  ratio,  using  the  curve,  -^  =  43° 

.  * .  A  =  86° 


5.07 
Average  2.53  equals  "Ratio." 

A 


Then 


or 


16.0    =  16.0 
tan  43°      0.933 

11.9         11.9 
sin  43°      0.680 


or  17.2 


or  17.5 
34/7 


Average  17.35 


62 


The  Engineer  in  Field  and  Office 


Area  inclosed  by  the  tangents  and  the  radii,  17.35  X  16.0 

equals    277.5 

Area  of  segment  of  circle,  86/360  X  «  X  17.352  equals  .   226.0 


J  51.5  sq.ft. 
5.7  sq.yd. 

If  the  curve  is  considered  as  a  parabola,  the  area  might  have 
been  calculated  in  the  following  manner,  but  it  does  not  seem  at  all 
certain  that  the  result  is  as  near  the  actual  value  as  is  obtained 
by  the  method  outlined  above. 


Area-  2  X 


Area  = 


^=  43.7  sq.ft. 
J  =    4.85  sq.yd. 


It  may  be  seen  that  the  first  method  is  more  likely  to  give  a 
better  result  than  the  one  based  upon  the  curve  being  a  parabola, 
because  more  measurements  are  utilized.  However,  either 
assumption  will  simplify  the  computation  over  the  usual  method. 

Sidewalks  Flushed  Over  Tops  of  Parked  Automobiles 

The  downtown  sidewalks  as  well  as  the  streets  in  Chicago  are 
flushed  every  night.  To  expedite  the  sidewalk  work,  there  has 


Extension  Pipe  When  Not  in  Use  Folds  Over  Top  of  Tank 

recently  been  added  to  one  of  two  tank  trucks  a  pipe  extension  to 
clear  parked  automobiles.     It  is  connected  to  the  discharge  line 


Municipal  Engineering  63 

from  the  pump  with  a  stuffing-box  joint  and  has  a  knee  brace  of 
the  same  2i-in.  pipe  as  the  remainder  of  the  line.  A  single  outfit 
can  flush  the  whole  72,000  sq.yd.  of  area  in  the  territory  covered 
in  an  8-hour  night  at  a  cost  of  20c.  per  1000  sq.yd.  It  is  usual, 
however,  to  let  the  two  trucks  work  at  the  job,  although  from  the 


Parked  Automobiles  Are  Not  Disturbed  by  Sidewalk  Flusher 

second  one  the  hose  must  be  dragged  behind  vehicles  near  the 
curb.  The  remainder  of  the  night's  work  is  to  flush  the  120,000 
sq.yd.  of  pavement.  The  fan  nozzle  is  6  in.  wide  and  delivers  a 
stream  i  in.  thick.  It  is  played  toward  the  gutter  and  carries  the 
dirt  and  surplus  water  ahead  of  it.  No  complaint  of  damage  to 
walks  or  calking  has  been  made.  When  the  second  tank  is  equipped, 
the  connection  will  be  made  near  the  front  of  the  tank,  so  that 
there  will  be  no  danger  of  bending  the  pipe,  should  the  truck  run 
it  into  something  when  half-way  extended. 

A  Modern  Intersection  for  Paved  Roads 

It  is  appreciated  by  automobile  drivers  that  the  loss  of  momentum 
and  time  due  to  slowing  down  to  turn  a  90°  corner  within  the  limits 
of  a  50-ft.  highway  is  about  equivalent  to  that  required  to  travel 
some  1500  ft.  on  a  tangent  of  similar  grade.  Another  difficulty  with 
the  usually  designed  intersection  is  the  lack  of  sufficient  clear-sight 
to  enable  the  driver  to  realize  the  approach  of  a  motor  on  an 
intersecting  road.  To  overcome  these  difficulties,  the  design  shown 
in  the  accompanying  illustration  has  been  put  forward;  and  as  may 


64 


The  Engineer  in  Field  and  Office 


be  seen,  within  the  limits  of  the  proposed  highway  the  clear-sight 
is  132  ft.,  though  in  reality  it  would  be  much  more  than  this  if  the 
regulations  concerning  vegetation  were  enforced. 

While  the  total  area  of  pavements  in  the  proposed  design  is 
1703.6  sq.yd.,  only  739.6  of  this  is  necessary  for  the  curve  connection 
shown,  the  remaining  954  sq.yd.  constituting  482  lin.ft.  of  main-line 
pavement,  18  ft.  wide.  Pavements  18  ft.  wide  being  ample  for  two 


A  Construction*! 


Proposed  Intersection  Gives  136-Ft.  Clear-Sight 

lines  of  motor  traffic  at  high  speed,  they  need  not  be  made  still 
wider  on  curves  where  speed  is  necessarily  reduced.  Likewise, 
there  would  seem  to  be  no  good  reason  for  widening  10-ft.  pave- 
ments on  curves;  15-  or  16-ft.  pavements,  however,  should  be 
widened  to  18  ft. 

Brick  and  concrete  pavements  are  generally  crowned  2  in.  The 
preservation  of  this  crown  at  the  intersection  would  prove  ob- 
jectionable, so  it  should  be  reduced  at  the  intersection  to  about  i 
in.  and  tapered  out  to  the  full  crown  in  a  distance  of  about  10  ft. 
in  each  direction. 

Sections  like  G,  H,  J,  K,  L,  P,  Q,  R  should  be  built  monolithic 
with  the  usual  convexity  of  surface  at  /,  K,  although  J  is  depressed. 


Municipal  Engineering 


65 


Areas  like  H,  J,  K  will  come  out  warped  surfaces  easily  built  by  an 
experienced  contractor.  The  10  construction  joints  shown  should 
be  nothing  more  than  planes  of  cleavage.  Sections  like  K,  E,  F, 
J,  which  are  built  last,  have  their  corner  elevations  fixed  by  the 
main  pavement.  The  usual  convexity  of  surface  is  preserved, 
therefore,  and  the  inner  edge  F,  J  is  depressed  to  meet  the  required 
elevation. 

In  areas  like  K,  L,  E  the  surface  of  the  ground  should  be  kept 
about  1  in.  below  that  of  the  surface  of  the  pavement  adjacent.  The 
catchbasins  and  drains  will  keep  the  ground  dry. 

Setting  Street-Corner  Radius  Stake 

In  setting  radius  stakes  for  street  corners  where  the  angle  of 
the  intersecting  streets  is  not  a  right  angle,  the  solutions  shown  in 
the  following  sketch  save  considerable  time  in  finding  the  correct 
location  for  the  radius  stake. 

Two  methods  may  be  used:  (1)  with  transit  at  E,  the  inter- 
section of  the  curb  line  and  the  center  line  of  the  intersecting 


Radius 
State 


u t. ,»i 

Diagram  for  Setting  Street-Corner  Radius  Stake 

street;    (2)  with  transit  at  F,  the  intersection  of  the  center  line 
of  the  two  intersecting  streets.     Considerable  time  and  instrument 
work  are  saved  by  using  the  method  with  F  as  instrument  point. 
For  method  1,  transit  at  E,  the  formulas  are: 


x  = 


tan  A  = 


sin  B 
R 


y  =  R  cot  i  B 

z  =    R 

sin  A 


66 


The  Engineer  in  Field  and  Office 


For  method  2,  transit  at  F,  the  formulas  are: 


= 
x 


a 
tan  o  = 


sinB 

-^- 
tanB 

R  +  M 


y  =  R  cot\  B 

L  =  x+  y  + 
R  +  M 


sine 


Street  Assessments  in  a  Hillside  Town 
It  is  believed  that  the  results  obtained  by  this  method  for  making 
street  improvement  assessments  in  a  hilly  town  with  crooked  streets 
and  irregular  lots  are  more  nearly  equitable  than  those  obtained 
by  the  ordinary  front-foot  method. 


Fitting  Assessments  to  a  Steep,  Crooked  Street 

Arrows  indicate  upgrades.     Heavy  line  shows  assessment  district  boundary. 
Frontages  given  in  feet  and  tenths 

The  following  factors  are  taken  into  consideration:  (1)  Front- 
age; (2)  area;  (3)  assessed  valuation;  (4)  the  benefit  or  damage 
to  each  lot  by  virtue  of  its  new  position  with  relation  to  the  graded 
street;  (5)  correction  for  over-assessment,  where  the  rates  would 
be  excessive. 

The  method  of  making  the  assessment  is  as  follows :  The  entire 
cost  to  be  assessed  is  distributed  in  amounts  directly  proportional 
to  (1)  the  frontage,  (2)  the  area  and  (3)  the  value  as  shown  in 
Columns  5,  6  and  7  of  the  table.  The  mean  of  these  values  is  then 


Municipal  Engineering 


67 


computed  (Column  8).  To  this  mean  a  benefit  or  damage  factor 
is  applied  varying  with  the  relative  position  of  the  lot  with  reference 
to  the  street  surface  before  and  after  grading.  The  figure  obtained 
in  Column  8  in  the  case  of  lots  in  Class  1  (considerably  damaged 
by  grading)  are  multiplied  by  §;  lots  of  Class  2  (slightly  damaged), 
by  §;  lots  of  Class  3  (neither  benefited  nor  damaged),  by  1;  lots 
of  Class  4  (slightly  benefited),  by  $;  and  lots  of  Class  5  (consider- 
ably benefited) ,  by  i.  The  results  after  this  operation  are  shown 
in  Column  10.  A  wider  and  more  refined  variation  could  be  applied 
in  cases  where  the  conditions  warrant  it.  The  sum  of  the  quantities 
in  Colmun  10  is  seldom  equal  to  the  total  cost  to  be  assessed,  so 
that  the  difference  between  the  sum  of  Column  10  and  the  desired 
total  is  distributed  in  proportion  to  the  values  found  in  Column  10 
(added  in  the  case  of  the  example).  The  corrected  quantities  are 
given  in  Column  11.  An  inspection  of  Column  11  shows  that  Lots 
66,  68  and  69  are  assessed  an  amount  in  excess  of  50%  of  the  tax 
assessor's  valuation — a  percentage  which  has  often  been  held  to 
be  a  confiscatory  rate.  These  amounts  are  then  reduced  to  a  sum 
slightly  below  50%  of  the  value,  and  the  excess  is  then  distributed 
at  a  uniform  rate  over  the  remaining  lots,  giving  the  final  values 
shown  in  Column  12. 

The  example  given  is  for  the  improvement  of  Central  Ave.  shown 
on  the  diagram    (Fig.  1). 

METHOD    OF   COMPUTING   STREET    IMPROVEMENTS    ACCORDING    TO 

FRONTAGE,   AREA   AND   VALUE,    WITH    BENEFIT 

FACTOR  ADJUSTMENT 


Lot 

Frontage,         Area, 
Ft.                Sq.Ft. 

Value 

,  —  Cost  Distributed  According  to  —  > 
Frontage              Area                Value 

(1) 

(2) 

(3) 

(4) 

(5) 

(6) 

(7) 

16 

20 

59.5 

84.0 

6,900 
12,000 

$1000 
800 

$152.26 
214.96 

$177.94 
309.45 

$211.05 
168.84 

21 

0.0 

23,500 

1000 

0.00 

606.01 

211.05 

66 

197.6 

7,100 

400 

505.66 

183.08 

84.42 

68 

80.0 

4,000 

300 

204.72 

103.15 

63.32 

69 

179.8 

3,300 

300 

460.10 

85.10 

63.32 

Mean  of 

Class  of 

Col.  8  with 

Col.  10 

Final  Cost 

Lot 

Cols.  5,  6,  7 

Benefit      Benefit  Factor 

Adjusted 

Distribution 

(1) 

(8) 

(9) 

(10) 

(11) 

(12) 

16 

$180.42 

1 

$120.28 

$126.37 

$136.08 

20 

231.08 

3 

231.08 

242.33 

260.95 

21 

272.35 

4 

317.73 

332.97 

358.20 

66 

257.72 

3 

257.72 

270.17 

199.00 

68 

123.73 

5 

164.96 

172.94 

149.00 

69 

202.84 

2 

169.05 

177.44 

149.00 

Home-Made  Portable-Pump  for  Manholes 

A  portable  centrifugal-pump  outfit  to  unwater  manholes  has 
recently  been  put  together  in  the  shops  of  the  Lincoln  Park  Com- 
mission, Chicago,  for  use  in  draining  the  electrical  underground 


68  The  Engineer  in  Field  and  Office 

distribution  system.  The  equipment  is  mounted  on  low  wheels  and 
can  be  hauled  by  an  automobile  or  a  truck.  The  12-hp.  1500-r.p.m. 
marine-type  gasoline  engine  is  direct-connected  to  a  centrifugal 
pump  rated  at  500  gal.  per  min.  at  2000  r.p.m.  Accessories  to  the 
pump  and  engine  are  a  23-gal.  gasoline  tank,  5-gal.  automobile 
radiator,  a  20-gal.  circulating-system  tank  and  a  66-gal.  primary 
tank.  With  the  available  speed,  4-in.  intake  and  3-in.  discharge 
hose,  300  gal.  per  min.  can  be  pumped  against  a  15-ft.  head, 
including  suction  and  discharge,  but  water  may  be  lifted  30  feet. 

Control  of  the  entire  outfit,  including  the  spark  and  gasoline 
levers,  the  outlet  and  air-vent  valves  and  the  valves  on  the  circulating 
system,  are  all  grouped  at  the  front  end  of  the  machine  within  easy 
reach  of  one  man. 

Means  have  been  provided  for  obtaining  easy  access  to  any  part 
by  making  the  inclosing  walls  either  hinged  or  entirely  removable. 
The  pump  has  proved  its  value  in  pumping  dry  a  line  of  ten  3-in. 
ducts  that  lie  along  the  shore  of  Lake  Michigan  and  are  arranged 
to  drain  from  one  manhole  to  another. 

A  detailed  statement  of  the  cost  of  constructing  this  outfit  in 
the  shops  of  the  commission  is  given  in  the  accompanying  table. 

COST  OF  BUILDING  EMERGENCY  WATER  PUMP 
MATERIAL 

1  marine  engine  and  muffler $90.00 

1  radiator    25.00 

To  build  truck  for  engine  pump  and  wheels 225.80 

To  install  engine  on  pump  truck 69.07 

Painting  pump   truck 21.54 

To  supplying  suction  hose,  valve  and  fittings 125.89 

Three  IJ-ft  valves    2.82 

1    cap    .10 

12  bolts,  various  sizes .12 

5  pipe  plugs,  various  sizes .36 

5  bushings,    various    sizes .45 

12-ft.  water  pipe,  various  sizes 2.34 

28  nipples,  various  sizes 2.24 

4  tees,  various  sizes .30 

6  unions,   various    sizes .99 

56  screws  and  nuts,  various  sizes 1.00 

19  ells,   various    sizes 1.61 

6    padlocks,   various   sizes 660 

Miscellaneous    material    24.13 

Total    $599.86 

LABOR 

Mechanic,   31   hours   at   50c <R-I  c  en 

Helper,  104  hours  at  32c '.'.'.'.'.'.'.'.'.'.'.'.  33.28 


Total    «48  78 

Garage  expense  (overhead) 120^85 

Grand  total $769.49 

All-Concrete  Road  Sign 

Competition  for  the  official  state-aid  road  sign  for  Illinois,  which 
the  State  Highway  .Department  announced  last  June,  brought 
designs  from  about  75  competitors  throughout  the  United  States, 


Municipal  Engineering 


69 


from  California  to  Massachusetts.  It  was  stipulated  that  the  draw- 
ings should  illustrate  the  proposed  type  of  sign  to  be  erected  along 
all  state-aid  roads. 


This  Is  the  Design  Which  Won  the  Prize  Competition  for 
Illinois  Road  Signs 

The  accompanying  illustration  shows  the  successful  design.  It 
was  selected  because  of  its  simplicity  and  durability,  and  its  evident 
ability  to  serve  the  purpose  to  which  it  will  be  put.  The  sign  is  of 
concrete  construction. 

Garbage  Collection  by  Motor  Truck 

The  City  of  Los  Angeles  collects  its  garbage  without  cost  to  the 
residents,  the  department  being  maintained  by  general  taxation. 
Garbage  is  delivered  under  contract  to  a  corporation  organized  to 
operate  a  disposal  plant  for  handling  garbage  and  other  refuse 
produced  by  the  city.  The  contract  stipulates  that  the  company  pay 
the  city  51c.  per  ton  delivered  for  all  garbage. 

The  city  is  divided  into  two  zones,  in  one  of  which  garbage  is 
collected  by  teams  and  in  the  other  by  motor  trucks.  For  the  latter 
the  full-load  haul  ranges  from  six  to  nine  miles,  averaging 
approximately  eight  miles.  In  this  zone  a  total  of  about  300  tons 
of  garbage  is  collected  each  month  by  two  2i-ton  motor  trucks  at  a 


70  The  Engineer  in  Field  and  Office 

cost  of  $2.76  per  ton.  Noncombustibles  in  both  districts  are 
collected  by  seven  24-ton  trucks  that  bring  in  a  total  of  about  3300 
cu.yd.  of  rubbish  per  month  at  a  cost  of  94c.  per  cubic  yard. 

The  cost  of  operating  the  trucks  ranges  from  $210  to  $250  per 
month.  This  includes  fuel,  driver,  lubricants,  repairs  and  deprecia- 
tion, but  is  exclusive  of  the  two  garbage  collectors  who  accompany 
each  truck.  The  trucks  average  two  or  more  loads  per  day  and  haul 
an  average  of  2|  tons  per  load.  Before  trucks  were  adopted,  these 
collections  were  made  by  three-horse  teams,  each  of  which  made  a 
single  round  trip  each  day.  The  use  of  motor  trucks  for  the  outlying 
districts  has  proved  so  satisfactory  that  the  city  would  not  consider 
a  return  to  the  use  of  teams  for  this  zone. 

The  short-haul  zone  is  served  by  teams  using  both  day  and  night 
shifts.  The  night  shift  has  a  monthly  average  of  2800  tons  at  a 
cost  of  about  $1.18  per  ton.  The  day  shift  averages  about  2200  tons 
per  month  at  a  cost  of  $2.15  per  ton. 

Home  District  for  Industrial  Workers 

A  ninety-acre  tract  of  land  on  the  southern  boundary  line  of 
the  City  of  San  Francisco  has  been  purchased  and  is  being  laid  out 
and  improved  as  a  district  in  which  the  average  industrial  worker 
will  be  able  to  purchase  his  own  home.  Building  lots  in  the 
residential  district  are  far  beyond  the  reach  of  the  average  mechanic ; 
and  as  a  result  the  steadiest  and  best  class  of  workmen  have  been 
locating  in  cities  across  the  bay.  This  action  has  tended  to  attract 
industries  to  those  cities  and  away  from  San  Francisco. 

The  project  contemplates  the  construction  of  a  large  number  of 
small  houses  which  will  be  sold  on  such  terms  that  the  monthly 
installments  will  amount  to  about  the  same  as  the  rental  such 
families  usually  pay,  the  total  cost  to  be  about  $2500  or  $3000.  The 
improvement  of  the  entire  tract  at  once  and  the  favorable  location 
of  lines  of  transportation,  schools,  retail-market  centers,  etc.,  make 
it  possible  to  offer  the  industrial  worker  a  proposition  that  is 
expected  to  have  a  notable  effect  on  the  San  Francisco  labor  problem. 

The  single  houses  are  to  be,  in  general,  of  the  bungalow  type, 
containing  four  rooms  and  bath  and  all  modern  conveniences.  The 
prices  fixed  on  50  x  100-ft.  lots  average  less  than  $500.  Other 
quarters  for  unmarried  men  are  contemplated,  and  it  is  expected 
that  the  plan  will  be  based  on  somewhat  the  same  idea  as  the  "com- 
munity houses"  in  England's  industrial  districts. 

The  plans  contemplate  the  ultimate  accommodation  of  15,000 
people  in  this  district,  which  is  not  far  from  the  new  Southern 
Pacific  shops,  where  about  5000  men  are  employed.  The  site  is 


Municipal  Engineering  71 

also  near  the  large  dry  dock  under  construction  at  Hunters  Point 
and  is  within  easy  reach  of  what  is  known  as  the  industrial  section 
of  the  city. 

Every  Culvert  is  Numbered 

Hamilton  County,  Ohio,  of  which  Cincinnati  is  the  county  seat, 
places  a  cast-iron  sign  with  the  name  of  the  highway  and  the  number 
of  the  culvert  on  the  parapet  and  wing-walls  of  every  culvert. 


Number  of  Culvert  and  Name  of  Road  Help  Officials  and  Tourists 

The  accompanying  illustration  shows  a  culvert  at  the  intersection 
of  two  roads,  the  Cincinnati-Dayton  intercounty  highway  and  the 
road  at  right  angles,  Kemper  Road.  These  signs  are  a  great 
convenience  to  tourists  and  also  assist  the  office  record  system. 

Street  Signs  Show  House  Numbers 

It  is  sometimes  hard,  even  to  one  who  is  acquainted  with  a  city's 
streets,  to  tell  from  the  corner  signs  just  how  near  he  is  to  the 
particular  house  number  he  is  seeking.  If  the  seeker  is  in  a  street 
car,  the  situation  is  aggravated.  Particularly  is  this  so  in  cities 
where  the  house  numbers  bear  no  relation  to  the  distance  of  the 
cross-streets  from  a  meridian  street.  The  new  style  of  street  sign 
adopted  by  Cincinnati,  Ohio,  avoids  this  difficulty.  All  streets  having 
car  lines  are  now  supplied  with  the  new  signs,  which  show  on  a 
separate  panel  the  numbers  of  the  corner  houses.  This  is  an 
admirable  advance  over  the  design  used  for  the  more  important 
street  signs  of  New  York  City,  which  show  the  crossing  street  in 
smaller-size  lettering  above  the  indicated  street. 


72  The  Engineer  in  Field  and  Office 

Drinking  Fountain  Attached  to  Hydrant 

A  street  drinking  fountain  supplied  from  the  hose  connection  of 
a  fire  hydrant  at  Galion,  Ohio,  is  shown  by  the  accompanying  view, 
in  which  the  small  vertical  pipe  at  the  left  supports  the  fountain 
and  serves  as  a  waste  connection  to  the  sewer.  The  supply  line  is 
tapped  into  a  nipple  screwed  into  one  of  the  two  hose  outlets.  This 
arrangement  necessitates  the  main  valve  of  the  hydrant  being  kept 
partially  open — enough  at  least,  to  bleed  sufficient  water  for  the 


Drinking  Fountain  on  Fire  Hydrant 

fountain.  A  self -draining  hydrant,  unless  accurately  adjusted, 
might  waste  considerable  water  if  adopted  to  this  scheme,  and  in  any 
case  a  valve,  too  far  opened,  would  have  to  be  closed  before  steamer 
connections  could  be  made  to  the  hydrant. 

Spokane  Installs  Low-Cost  Street  Signs 

Simple,  legible,  low-cost  street  signs  are  being  installed  in 
Spokane,  Wash.,  as  shown  by  the  accompanying  illustration.  Each 
sign  consists  of  two  enameled  porcelain  plates  secured  to  a  creosoted 
wood  base  and  held  by  a  bracket,  clamped  to  a  lamp  post.  The 
wood  base  is  so  shaped  as  to  make  each  nameplate  rest  at  a  slight 


Municipal  Engineering 


73 


angle  with  the  vertical,  so  the  street  light  from  above  casts  no 
shadow  on  the  nameplate.    Each  of  the  four  plates  attached  to  one 


Spokane  Using  Street  Signs  Like  This 

lamp  post  costs  $0.35,  and  the  two  brackets  together  cost  $1.15, 
making  a  total  cost  of  $2.55  for  plates  and  brackets  at  a  given  corner. 
The  cost  of  the  wood  and  of  erection  is  small. 

White  Bridges  Can  Be  Seen  at  Night 

The  practice  of  painting  highway  bridges  white  so  as  to  increase 
their  visibility  and  thereby  decrease  possible  accidents,  is  growing 


White  Bridge  Is  Readily  Seen 

People  who  cross  this  bridge  at  night  who  are  accustomed  to  black 
or  red  bridges  are  struck  with  the  ease  with  which  the  outlines  of 


74  The  Engineer  in  Field  and  Office 

the  bridge  are  noted.  In  Putnam  County,  Ohio,  several  truss  bridges 
have  been  painted  as  shown  in  the  view.  The  end  posts  of  truss 
and  railing  are  white  for  their  full  length  but  the  inner  railings  and 
posts  up  to  a  height  of  4  ft.  are  painted  black  as  a  protection 
against  discoloration. 

Present-Day  Water- Works  Construction, 
Maintenance,  Operation  and  Repairs 

Dynamiting  a  Deep  Well 

A  water  well  near  Kennett  Square,  Penn.,  was  "shot"  a  short 
short  time  ago  to  increase  the  flow.  It  was  600  ft.  deep,  started  at 
the  top  of  a  hill  of  elevation  460  ft.  After  drilling  through  84  ft. 
of  stiff  clay  and  hardpan,  solid  rock  was  encountered  with  successive 
strata  as  follows: 

Ft.  Ft. 

Sand  rock 121.0  Gray    granite    with    green    ser- 

Flint  rock   90.0            pentine   seams    2.0 

Blue  granite 17.5       Gray   granite    40.0 

White  quartz    1.2       Blue  granite 3.0 

Gray  granite    47.8       Gray   granite    72.0 

Blue  granite 17.5       Bastard   granite    84.0 

Gray  granite  with  quartz  seams  10.0                                                                      

Blue   granite   broken 10.0           Total   516.0 

An  8-in.  steel  casing  was  sunk  to  rock  and  grouted  to  exclude 
surface  drainage;  the  hole  through  the  rock  was  6  in.  At  600  ft. 
the  flow  was  measured  and  found  to  be  only  3i  gal.  per  min.  To 
go  deeper  would  mean  expensive  pumping  equipment.  It  was 
thought  that  a  discharge  of  nitroglycerin  would  shatter  some  of 
the  water-bearing  strata. 

Indications  were  that  the  stream  supplying  the  well  was  about 
320  ft.  below  ground  level.  Just  below  this  point  the  well  was 
bridged  by  means  of  a  ball  of  stiff  wire  forced  to  the  desired  depth. 
Concrete  was  placed  upon  this.  A  special  type  of  solidified  nitro- 
glycerin— which  is  commonly  used  for  shooting  oil  wells — formed 
the  charge,  which  consisted  of  190  qt.  The  explosive  was  packed  in 
10  tubes,  5f  in.  in  diameter  and  7  ft.  long.  These  were  placed 
in  the  well  one  above  another,  and  the  whole  was  discharged  by 
dropping  a  jack  squib  down  the  well. 

A  column  of  water  500  ft.  high  was  blown  from  the  well, 
following  which  the  latter  was  tested.  The  test  pump  working 
continuously  for  7  hr.  pumped  10,000  gal.,  which  was  at  the  rate 
of  22  gal.  per  min. 


Water  Works 


75 


An  Aid  to  Reservoir-Storage  Studies 

In  studies  of  natural  or  artificial  reservoirs  for  storage  purposes, 
it  frequently  is  necessary  to  determine  the  rise  or  fall  in  the  surface 
level,  due  to  certain  rates  of  outflow  and  inflow.  If  the  outflow  is 
not  constant  for  the  varying  levels,  the  required  rise  or  fall  due 
to  a  given  inflow  is  ordinarily  arrived  at  by  a  laborious  trial  method 
until  a  balance  is  reached  between  the  various  factors.  For 
illustration  of  the  method  herein  described,  let  a  reservoir  of  100 
sq.mi.  be  assumed,  with  a  discharge  curve  as  shown  by  the  heavy 
line  in  the  figure.  The  theoretical  rate  of  inflow — including  rainfall 


0  2          4          6          8          10         12 

Inflow  into  Reservoir,  Thousand  Cubic  Fee*  per  Second 
(Negative  Inflow  denotes  Evaporation  or  Seepage  Loss) 

Chart  for  Determining  Change  in  Surface  Level  of  Reservoir 

on,  and  evaporation  and  seepage  from  the  reservoir — is  equal  to 
the  average  rate  of  outflow  from  the  reservoir  plus  or  minus  the 
rate  produced  by  the  rise  or  fall  in  the  surface  level  over  the  given 
period.  By  assuming  several  initial  levels  within  the  limit  of 
probable  requirements,  and  several  rates  of  rise  and  fall  during  a 
period  of  15  days,  the  corresponding  inflow  is  determined,  upon 
which  the  remaining  curves  in  the  figure  are  based.  In  using 
such  a  chart  the  above  process  is  merely  reversed.  Given  any  inflow, 
and  a  certain  reservoir  level  at  the  beginning  of  the  period,  the  rise 
or  fall  during  the  period  may  be  directly  taken  off.  For  a  level 
of  102  and  an  inflow  of  10,000  sec.-ft.,  the  reservoir  will  rise  1.25 
ft.  during  the  half  month.  The  chart  may  be  constructed  for  any 
shape  of  outflow  curve,  and  for  any  period  of  time,  and  where  there 
are  a  considerable  number  of  computations  to  be  made  it  will  prove 
a  time-saver. 


76 


The  Engineer  in  Field  and  Office 


Temperature  and  Water  Consumption 

The  accompanying  curves  show  a  notable  similarity  between  the 
number  of  hours  of  pumping  per  month  and  the  average  temperature 
per  month  for  a  suburban  water  plant  in  Maryland.  The  plant  has 


Temperature  and  Water  Consumption 

five  deep-well  pumps,  7i  mi.  of  4-  and  6-in.  main,  and  supplies  a 
high-grade  suburban  development.  All  services  are  metered,  and 
there  is  very  little  leakage  from  the  mains. 

Liquid  Chlorine  Superior  to  Hypochlorite 

Liquid  chlorine  cost  much  less  and  effected  more  bacterial 
reduction  than  hypochlorite  and  was  in  other  respects  more 
satisfactory  on  an  Illinois  installation.  With  hypochlorite  at  7c. 
and  liquid  chlorine  at  20c.  the  average  cost  of  hypochlorite  treatment 
for  January  was  $1.07,  compared  with  only  $0.28  per  1,000,000  gal 
for  liquid  chlorine. 

The  average  reduction  in  bacteria  count  of  daily  plates  made  on 
nutrient  agar  incubated  at  37°  C.  for  24  hours,  was  as  follows: 
In  January  when  hypochlorite  was  used  the  average  raw-water  count 
was  6300  and  the  filtered- water  count  was  15.  In  June,  when  liquid 
chlorine  was  used,  the  average  raw-water  count  was  7980  and  the 
filtered-water  count  was  11.  In  B.  Coli  tests,  the  raw  water  shows 
100%  for  each  month,  while  the  filtered  water  shows  1.6%  in 
January  and  0.0%  in  June.  These  results  were  obtained  by  means 
of  1  c.c.  samples  in  all  cases.  Also  note  that  while  hypochlorite 
was  used  0.46  p.p.m.  of  available  chlorine  was  applied  and  while 
using  liquid  chlorine  0.22  p.p.m.  of  chlorine  was  applied. 


Water  Works 77 

Deep  Wells  Cost  0.82  Cent  per  1000 
Gallons   To  Operate 

Costs  of  maintaining  and  operating  for  16  months  five  deep  wells 
supplying  the  University  of  Illinois  were  equivalent  to  an  average  of 
$151  per  year,  or  0.82c.  per  1000  gal.  The  following  data  were 
given  at  the  recent  meeting  of  the  Illinois  section  of  the  American 
Water- Works  Association : 

Capacity  Percentage 

, First  Cost ,  of  Pump  °fDay 

Well  Casing       Motor  and  Operating  Cost               Gal.  Pump  Was 

Well       and  Screen        and  Pump  Labor       Material  per  Min.  in  Operation 

A                   $559                     $375  $172.07        $100.26                 60  44 

B                     546                        813  56.51               2.26                 69 

C                      699                        788  202.73            82.86                 81  70 

D                   1348                       758  113.05            42.93                 71  86 

E                    891          .            810  147.26            88.08                75  89 

The  wells  have  been  drilled  about  140  ft.  deep  into  glacial  drift, 
and  the  water  stands  about  110  ft.  below  the  surface  when  pumping 
is  in  progress.  The  pumps  had  been  in  use  for  periods  ranging  from 
one  to  eleven  years ;  hence  the  results  are  believed  to  represent  fairly 
well  the  average  performance  of  the  pumps  during  their  useful  life. 

The  chief  cause  of  trouble  is  the  fine  sand  getting  into  the  well 
and  into  the  pump.  Rods,  couplings,  working  barrel  and  packing 
are  worn  quite  rapidly.  The  conditions  under  which  the  pumps 
work  are  thought  decidedly  poor. 

Paper  Replaces  Hemp  for  Pipe  Joints 

Pipe- joint  materials  became  so  scarce  on  account  of  the  war 
demands  that  a  paper  packing  for  joints  of  cast-iron  and  steel  pipes 
has  been  tried  in  Zurich,  Switzerland. 

The  packing  is  made  of  rolls  of  newspaper,  conical  in  form, 
6  in.  long,  i  in.  to  i  in.  in  diameter,  nested  together  and  pasted. 
They  are  waterproofed  by  impregnating  with  tar  oil.  They  are 
flexible  and  compressible  and  can  be  driven  very  tight  with  a  calking 
iron.  A  f-in.  lead  joint  is  poured  over  the  paper,  but  even  without 
this  such  joints  held  a  pressure  of  750  Ib.  per  sq.in.  after  14  days 
in  water. 

Filter  Wash  Water  Pumped  by  Compressed  Air 

Having  on  hand  two  sheet-steel  tanks  of  29,000-gal.  capacity 
and  an  air  compressor  with  plenty  of  off-peak  time,  the  designers 
of  the  Lawrenceville,  111.,  filter  plant  were  enabled  to  eliminate  the 
purchase  of  a  wash-water  pump,  the  compressor  being  available  to 
store  up  sufficient  air  under  pressure. 


78  The  Engineer  in  Field  and  Office 

The  plant  consists  of  two  rapid  filters  of  180  sq.ft.  filtering  area 
each,  with  the  usual  system  of  strainers  fitted  for  washing  at  a  rate 
of  2  ft.  vertical  rise  per  minute.  The  two  tanks  formerly  used  on 
the  distribution  system  as  storage  tanks  and  pressure  equalizers, 
were  available  for  air  storage. 

In  washing  a  filter  the  procedure  is  as  follows:  Starting  with 
the  tanks  three-fourths  full  of  water,  air  is  pumped  in  through  a 
2-in.  line  until  a  pressure  of  25  Ib.  per  sq.in.  has  been  attained.  The 
air  line  is  then  shut  off  adjacent  to  the  tanks,  and  the  compressor 
fills  an  air-storage  reservoir  of  340  cu.ft.  of  free  air  to  a  pressure 
of  80  Ib.  per  sq.in.  This  storage  is  on  the  air  line  leading  to  the 
wash-water  tanks.  When  the  required  pressure  is  attained  and  the 
storage  opened  into  the  line,  the  filter  wash  is  started.  By  proper 
manipulation  of  the  wash-water  valve  an  even  wash  can  be 
maintained  at  the  required  rate.  When  the  filter  has  been  washed, 
the  air  pressure  is  released  and  the  tanks  refilled  from  city  service. 
The  only  objection  reported  to  the  procedure  is  that  the  operator 
may  be  careless  and  not  give  proper  attention  to  the  manipulation 
of  the  wash-water  valve,  in  which  event  it  is  possible  to  blow  up  the 
sand  bed. 

New  Design  of  Screen  Chamber 

The  customary  method  of  removing  grass,  leaves,  sticks,  bits  of 
bark  and  fish  from  reservoir  and  lake  water  supplies  is  to  install 
either  a  screen  affixed  to  the  pipe  or  else  two  screens  in  series,  one 
of  which  may  be  drawn  up  out  of  the  water  for  cleaning  while  the 
other  is  in  service.  The  former  arangement,  which  is  applicable 
only  to  very  small  depths  of  water  on  the  screen,  is  economy 
itself  in  first  cost,  but  its  use  has  not  always  proved  so 
economical;  as  owing  to  any  one  of  many  causes  the  screen  might 
not  receive  the  necessary  attention  at  the  very  time  when  it  was 
most  needed.  The  latter  necessitates  a  considerable  structure  to 
hold  the  screens  in  place  and  house  them  while  being  cleaned, 
besides  the  trouble  and  expense  of  cleaning. 

To  obviate  these  and  other  difficulties  the  pressure  screen  chamber 
here  described  was  designed.  It  consists  essentially  (see 
illustrations)  of  a  vertical  cylinder  divided  by  a  horizontal 
diaphragm  into  two  compartments ;  the  upper,  or  inlet,  compartment 
has  communication  with  the  lower,  or  outlet,  through  a  circular 
opening  in  the  diaphragm  and  thence  through  the  meshes  of  an 
open-ended  cylindrical  screen  resting  in  the  lower  compartment,  of 
a  diameter  nearly  that  of  the  opening.  The  lower  end  of  the  screen 
is  concentric  with  the  end  of  a  blowoff  pipe  with  a  gate  valve  on  it, 


Water  Works 


79 


normally  closed.  The  inlet  pipe  enters  the  inlet  compartment 
tangentially,  while  the  outlet  may  leave  in  any  direction  relative 
to  that  of  the  inlet,  preferably  in  a  radial  position.  Any  flow  from 
the  inlet  pipe  sets  up  a  whirling  motion  in  the  water  in  the  upper 
compartment.  In  passing  through  the  screen  cylinder  it  has  a 
circumferential  as  well  as  a  downward  motion,  which,  owing  to  the 


..Connection  for 


Horizontal      Section  A-A 
Rein  forced-Concrete  Pressure  Screen  Chamber 

passage  of  water  through  the  meshes  of  the  screen,  diminishes 
as  the  bottom  of  the  screen  is  approached.  The  result  of  this  is 
to  confine,  largely,  the  foreign  matter  carried  by  the  water  to  a 
central  cone  the  base  and  height  of  which  are  approximately  those 
of  the  screen.  The  upturned  end  of  the  blowoff  pipe  being  made 
of  nearly  as  great  a  diameter  as  the  screen,  this  results  in  an 
accumulation  of  debris  directly  in  the  pipe.  When  blocking  of 
the  screen  has  progressed  to  a  point  at  which  there  is  a  noticeable 
loss  of  head  at  the  screen — as  measured  preferably  by  a  mercury 


80  The  Engineer  in  Field  and  Office 

U-tube  or  a  differential  gage — the  blowoff  gate  is  opened ;  the  head 
in  the  blowoff  pipe  is  then  reduced  to  zero,  or  nearly  so,  the  hydraulic 
gradient  from  reservoir  to  screen  chamber  is  increased,  and  the 
high  velocity  established  is  transmitted  directly  to  the  water  passing 
diagonally  downward  over  the  face  of  the  screen  and  out  the  blowoff 
pipe.  Ordinarily,  the  cleaning  of  the  screen  is  accomplished  in  about 
the  time  that  it  takes  to  open  and  close  the  blowoff  gate.  If  it  is 
desired  to  maintain  a  considerable  continuous  flow  through  the 
outlet  pipe,  the  blowoff  gate  need  not  be  opened  wide,  in  which  case 
the  operation  will  require  a  longer  time.  Under  no  conditions  is 
an  appreciable  amount  of  water  wasted. 

Also  incorporated  in  the  design  is  a  hollow  segmental  brush, 
for  use  in  cases  when  the  screen  does  not  get  attention  for  such 
long  periods  that  a  deposit  of  small  fish  is  not  readily  removed 
by  the  flowing  water.  For  the  intake  pipes  of  pumping  stations  the 
devices  are  best  set  in  batteries  of  two,  so  arranged  that  one  can 
be  put  in  service  while  the  other  is  being  cleaned.  In  this  case  the 
cleaning  is  preferably  done  by  jets  of  high-pressure  water  directed 
downward  from  the  edge  of  the  diaphragm  across  the  screen.  Where 
electric  power  is  available,  the  use  of  proper  contact  devices  at  the 
point  of  measurement  of  the  loss  of  head  at  the  screen  will  make 
the  entire  screening  operation  automatic,  both  for  gravity  and 
pumping  supplies. 

For  use  with  a  gravity  water-supply  the  devices  have  been  found 
to  operate  most  successfully  between  the  heads  of  40  and  60  ft., 
though  there  is  no  valid  objection  to  their  use  at  other  heads,  under 
certain  conditions.  The  screen  chambers  are  made  entirely  of 
reinforced  concrete  with  the  exception  of  the  manhole  cover,  which 
is  of  cast  iron. 

Geared-Up  Gas  Engine  Drive  Pumps 

Formerly,  water  was  supplied  in  Clarksburg,  W.  Va.,  by 
engine-driven  centrifugal  low-service  pumps  and  duplex  direct- 
acting  high-service  pumps,  both  taking  steam  from  gas-fired  boilers. 
When  additional  capacity  was  required  it  was  decided  to  use  pumps 
driven  by  gas  engines  in  view  of  the  rapid  depletion  of  the 
natural-gas  supply  of  the  district  and  the  necessity  of  making  the 
city's  fuel  wells  last  as  long  as  possible.  The  preliminary  estimates 
showed  that  the  gas-engine  units  would  demand  only  about  a  third 
of  the  fuel  needed  for  the  boilers  and  steam  machines. 

The  equipment  secured  after  bidding  comprised  a  4,000,000-gal. 
centrifugal  pump,  for  35-ft.  head,  driven  by  a  50-hp.  engine,  and  a 
4,000,000-gal.  pump,  for  350-ft.  head,  driven  by  a  350-hp.  engine. 


Water  Works 81 

The  small  unit  supplies  the  filter  beds,  and  the  larger  ones  pumps 
into  the  city  reservoir.  The  engine  speed  is  stepped  up  by  double 
helical  gears  from  200  r.p.m.  to  1385. 

During  a  10-day  continuous  run  the  total  gas  consumption  of 
both  units  averaged  82,200  cu.ft.  of  gas  per  day;  the  delivery  was 
held  up  to  4,100,000  gal.  per  day  against  330-  and  30-ft.  heads, 
giving  a  load  of  258.5  water  horsepower.  The  gas  comes  from  the 
city's  wells  and  is  charged  up  at  6c.  per  1000  cu.ft.,  although  the 
local  commercial  power  rate  is  8c.  At  6c.  the  fuel  costs  $6.96  per 
hp.  per  year,  or  0.079c.  per  hp.-hr. 

The  complete  cost  of  pumping  equipment  is  reported  to  have 
been  approximately  $17,500;  the  substructures,  superstructure, 
crane,  piping  and  appurtenances  cost  complete  $13,905,  bringing  the 
total  to  $31,405.  The  interest,  depreciation  and  upkeep,  figured  at 
10%  (equivalent  to  12%  on  machinery  and  8%  on  structures), 
would  be  $3140,  or  $12.18  per  hp.-year,  or  0.138c.  per  hp.-hr. 
0.217c.  per  hp.-hr.,  exclusive  of  labor  and  supplies. 

Electric  Tunnel  Lights  in  Closed  Box  for  Safety 

In  the  construction  of  the  recently  completed  Cleveland  west-side 
water-works  tunnel  all  lights  were  ordered  to  be  of  such  a  character 
that  they  could  not  ignite  the  explosive  mixture  of  gas  found  in  the 
tunnel.  The  cap  lamps  worn  by  the  men  are  of  the  storage-battery 
type,  locked  and  unlocked  above  ground,  but  the  lights  used  in 
construction  work  itself,  which  are  necessarily  larger,  are  built  into 
a  very  carefully  constructed  box. 

The  reflectors  are  "bullet"  automobile  headlights,  each  containing 
a  24-watt  lamp  that  is  protected  by  wire-glass  and  connected  to  a 
90  ampere-hour  storage  battery  set  midway  of  the  length  of  the 
box.  The  latter  is  13  in.  wide,  10  in.  high  and  23  in.  long,  outside 
dimensions,  and  is  lighted  and  locked  above  ground — the  key  being 
kept  there.  The  carpentry  work  on  the  boxes  is  of  a  very  high 
grade,  all  joints  being  tight,  serving  to  keep  the  explosive  gas  out 
of  the  box  as  much  as  possible,  in  the  event  of  a  spark  being  caused 
by  a  loose  connection  at  the  battery. 

Air  Valves  in  Large  Vented  Vaults 

Air  valves  on  the  newer  wood-stave  pipe  lines  bringing  water 
to  Denver,  Colo.,  from  the  mountain  sources  are  placed  in  large 
concrete  manholes.  Formerly,  it  was  the  practice  to  use  open 
manhole  covers,  but  they  have  been  discontinued  in  favor  of 
ventilating  pipes.  The  manholes  could  not  always  be  depended  upon, 
for  earth  and,  in  winter,  snow  and  ice  might  fill  the  openings. 


82 


The  Engineer  in  Field  and  Office 


For  a  2-in.  automatic  air  valve,  of  which  100  are  in  use,  set  on 
the  newer  lines  one  at  each  summit,  4-in.  ventilating  pipes  are  used 
extended  8  to  10  ft.  above  the  surface.  If  the  supply  pipe  happens 
to  be  laid  in  a  roadway,  the  ventilating  pipe  is  led  off  to  the  side 
or  even  inside  the  fence  line  to  protect  it  from  injury.  Small  holes, 
aggregating  in  area  many  times  the  area  of  the  air  valve,  are  bored 
near  the  top  of  the  pipe,  which  is  plugged  or  capped. 


f  Ground  Line  when  Manhofe  fs  Located  in  Oen  Field 
i 'Ground 


No  Collapses  with  This  Design 

The  air  valve  is  placed  on  top  of  the  pipe  with  a  return  bend 
on  the  outlet,  so  that  any  water  that  may  be  delivered  during  the 
periodical  test  will  not  drown  out  the  operator.  To  facilitate  testing, 
the  gate  valve  is  set  just  above  the  special  casting  through  which  the 
connection  to  the  wood  pipe  is  made.  Also,  a  hole  is  drilled  in  the 
lower  part  of  the  air-valve  body  for  a  pet-cock.  On  opening  the 
pet-cock  the  float  will  fall,  if  held  up  by  air  or  if  it  happens  to  be 
stuck.  If  water  is  holding  the  float  up,  the  operation  of  closing  the 
gate  valve  and  opening  the  pet-cock  will  make  the  float  work. 

Where  these  air  valves  have  been  installed  and  an  absolutely 
sure  source  of  air,  such  as  here  provided,  is  assured,  no  collapses 
have  occurred  and  the  pipes  are  kept  running  full,  the  air  being 
removed  as  fast  as  it  collects. 


Water  Works 


Cast-iron  Pipe  Connection  for  Wood-Stave  Pipe 

The  connection  of  a  wood-stave  pipe  with  a  concrete  structure  is 
a  troublesome  detail.  Quite  often  the  end  of  the  pipe  is  inserted 
into  a  socket  left  in  the  concrete.  Subsequently  the  ring  left  around 
the  pipe  is  grouted.  While  this  method  is  still  in  use  it  has  been 
the  cause  of  some  failures  in  wooden  siphons  in  Wyoming,  for  the 
repair  cannot  be  made  easily  when  it  becomes  necessary  to  replace 
the  staves. 

One  engineer  handles  the  problem  by  embedding  a  cast-iron  pipe 
in  the  concrete  and  then  fitting  the  wood  pipe  over  it.  To  make  a 
water-tight  joint  and  one  that  permits  expansion  and  contraction, 
the  cast-iron  pipe  is  wrapped  with  tar-soaked  oakum  for  a  distance 
of  4  ft.  Beginning  at  a  point  15  ft.  from  the  end  of  the  pipe,  the 
internal  diameter  of  the  wood  pipe  is  increased  by  tapered  staves 
to  fit  the  outside  of  the  wrapped  pipe. 

Pool  Floor  Forms  Are  Slotted  for  Water  Stops 

Forms  slotted  to  hold  the  water  stops  between  adjoining  floor 
blocks  were  required  in  laying  the  floor  of  a  large  pool  which  forms 
one  of  the  architectural  adornments  of  the  Kensico  dam  of  the  New 
York  City  water  supply.  This  pool,  which  is  720  ft.  long  and  135  ft. 
wide,  is  partly  in  cut  and  partly  on  a  rolled  earth  fill.  It  is 
surrounded  by  a  wall  5  ft.  thick,  surmounted  by  cut-stone  curbing, 
and  its  8-in.  concrete  floor  is  laid  on  porous  material  with  vitrified 
pipe  underdrains.  It  was  essential  to  make  this  floor  as  near 
watertight  as  possible.  The  floor  was  laid  off  in  9-ft.  squares  with 
a  joint  and  water  stop  between  adjacent  squares. 

Forms  for  the  floor  slabs  were  made  in  the  carpenter  shop  from 
6  x  8-in.  timbers.  A  longitudinal  groove  cut  along  one  side  of  each 
of  these  timbers  midway  between  the  top  and  bottom  provided  a 
setting  for  the  steel  water-stop  strip  to  be  embedded  in  each  block. 
Each  of  these  form  pieces  was  made  separate,  and  a  number  of 
different  lengths  ranging  from  a  little  less  than  9  ft.  to  about  9  ft. 
11  in.  were  turned  out,  as  the  progress  of  the  work  required  the 
form  strips  to  be  used  sometimes  between  blocks  already  cast  and 
sometimes  to  overlap  adjacent  blocks.  Forms  were  first  set  for 
alternate  blocks  in  each  direction,  and  when  these  blocks  were 
concreted  and  the  forms  removed  this  left  water-stop  strips 
embedded  in  the  first  blocks  on  both  sides  of  the  intermediate 
blocks  in  each  direction.  These  could  then  be  filled  in,  leaving 
holes  in  alternate  rows  in  each  direction  on  all  sides  of  which  the 
water-stop  strip  would  be  sticking  out. 


84  The  Engineer  in  Field  and  Office 

As  used  for  the  first  blocks,  the  four  sides  of  a  form  were 
clamped  in  place  by  clips  with  set  screws  just  outside  the  forms  at 
the  corners.  These  screws  gripped  the  water-stop  strips,  which 
were  laid  in  long  lengths,  gridiron  fashion,  over  the  foundation 
before  the  first  of  the  forms  were  set.  The  forms  were  wedged 
together  by  driving  steel  or  wood  wedges  between  the  clips  outside 
of  the  forms.  Altogether  about  350  form  pieces  were  made,  and  as 
a  rule  about  thirty  blocks  were  formed  with  them  at  one  time.  The 
same  pieces  were  used  continuously  throughout  the  work,  and  most 
of  them  lasted  the  job  in  good  shape. 

Steam  Jet  Clears  Coagulant  Line 

Steam  jets  replace  water  injectors  occasionally  on  the  coagulant 
lines  at  the  filtration  plant  in  Evanston,  111.  As  designed,  the 
coagulant,  after  passing  the  orifice  boxes,  is  forced  by  water 
ejectors  450  ft.  through  a  2-in.  lead  pipe  to  the  point  of  application. 
Considerable  trouble  from  the  alum  line  clogging  was  experienced, 
until  a  steam  connection  was  made.  After  using  steam  for  15  or 
20  min.,  coagulant  is  forced  through  the  pipe  with  water  in  the 
usual  manner.  This  cools  the  inside  of  the  pipe  rapidly,  causing 
the  scale  to  break  away.  Prior  to  this  practice  it  was  necessary  to 
clean  the  steam  line  once  a  week.  Once  in  two  months  is  the 
interval  of  time  since  using  the  steam  jet. 

Calcium  Oxide  Determined  by  Sugar  Solution 

The  following  is  the  method  in  use  in  the  laboratory  of  the  St. 
Louis  Water  Department  for  the  determinations  of  the  water- 
soluble  calcium  oxide  in  quick  lime.  Approximately  7  grams  of 
lime,  contained  in  a  weighing  bottle,  are  dumped  into  a  liter  flask 
containing  500  c.c.  of  a  sugar  solution  (160  grams  per  liter). 
Caking  is  prevented  by  causing  a  whirling  of  the  solution  while 
the  sample  is  being  added.  The  flask  is  then  put  on  a  Camp 
shaking  machine  and  shaken  for  30  minutes.  It  is  then  made  up 
to  the  1000  c.c.  mark  with  carbon-dioxide-free  distilled  water, 
shaken  by  hand  and  allowed  to  stand  overnight.  Twenty  cubic 
centimeters  of  this  solution  are  then  titrated  with  tenth-normal 
hydrochloric  acid,  using  phenolphthalein  as  the  indicator,  and  the 
per  cent  of  lime  determined.  The  addition  of  acid  is  continued  until 
the  first  disappearance  of  the  pink  color.  The  color  reappears  in 
a  short  time,  but  the  first  disappearance  is  taken  as  the  end  point. 


Water  Works 


85 


Steel  Pipe  Line  Covered  with  Concrete 

Old  riveted-steel  water  pipe  have  been  successfully  incased  in 
reinforced  concrete,  and  in  the  light  of  the  present  high  price  of 
steel  plates  the  work  may  be  of  interest  to  others  having  pipe  lines 
to  replace. 

These  details  were  worked  out  more  particularly  for  use  in 
covering  10,000  ft.  of  24-in.  riveted-steel  pipe  line  used  as  inverted 
siphons  working  up  to  80  ft.  head.  This  line  was  laid  30  years  ago 


ftott- 


Old  Steel  Inside  Form  for  New  Concrete  Pipe 


and  is  beginning  to  give  way  near  the  ends  of  the  siphons  where 
light  weight  steel  was  used  on  account  of  low  heads.  Possibly  95% 
of  the  iron  is  still  in  the  pipe,  but  it  has  rusted  badly  and  pitted 
particularly  at  the  seams,  so  that  it  has  been  necessary  to  make 
repairs  during  the  irrigation  season.  The  system  not  only  protects 
the  outside  of  the  pipe  and  prolongs  its  life  by  the  jacket  of 
reinforced  concrete,  but  eventually  utilizes  all  the  iron  in  the  old 
pipe,  and  when  it  has  disappeared  leaves  a  reinforced-concrete  pipe 
without  joints,  sufficiently  strong  to  carry  the  pressure. 


86  The  Engineer  in  Field  and  Office 

The  forms  are  constructed  of  Oregon  pine  and  lined  with  26 
gage  black  iron,  which  saves  not  only  the  forms  but  much  material, 
making  a  smooth  outside  surface  to  the  finished  pipe.  Forms  for 
24-in.  and  larger  pipe  are  made  in  8-ft.  lengths,  while  the  smaller 
sizes  are  made  up  in  12-ft.  lengths. 

After  the  steel  pipe  is  uncovered  it  is  thoroughly  scraped  and 
cleaned  with  steel  brushes.  The  ground  under  the  pipe  is  then 
shaped  to  the  required  depth,  the  pipe  being  supported  on  wood 
blocks  until  the  forms  are  set.  Bedplates  of  2  x  4s  are  then  spaced 
with  a  template,  similar  to  the  end  section  of  the  form,  on  each 
side  of  the  pipe  to  support  the  forms  when  in  place.  The  wire-mesh 
reinforcement  cut  to  50-  or  75-ft.  lengths  is  then  wound  spirally 
around  the  pipe  and  supported  where  the  edges  unite  by  small 
cement-mortar  blocks  made  in  the  form  of  truncated  pyramids,  li 
in.  high,  2  in.  square  at  the  base  and  I  in.  at  the  apex,  which  is 
placed  next  to  the  pipe.  A  man  with  a  hand  mold  will  make  2500  or 
3000  of  the  small  blocks  in  nine  hours.  The  edges  of  the  mesh  rest 
on  the  base  of  the  pyramid.  The  edges  of  the  wire  mesh  are  tied 
together  with  No.  24  soft  stovepipe  wire. 

The  forms  are  then  placed  on  the  2x4s  and  held  rigid  by  the 
two  i-in.  bolts  as  shown.  The  wood  blocks  supporting  the  pipe  are 
removed,  and  the  pipe  is  held  in,  place  by  a  strand  of  wire  and  a 
turnbuckle  clamp  until  the  form  is  filled  to  a  point  where  the 
concrete  will  support  the  pipe.  The  concrete  is  a  1 :  2£ :  1  mixture 
of  cement,  sand  and  crushed  rock  or  screened  gravel  of  l-in. 
maximum  size.  It  is  mixed  by  hand  and  poured  rather  wet,  being 
worked  to  place  with  a  light  rod  and  by  tapping  the  forms  with  a 
hammer.  In  laying  the  pipe  up  hill  the  top  openings,  as  the  forms 
are  filled,  are  closed  with  covers  clamped  to  place  until  the  concrete 
sets  slightly,  when  the  covers  are  removed  and  the  surface  is  well 
troweled  and  smoothed.  The  next  morning  the  forms  are  removed, 
and  the  pipe  is  painted  with  neat  cement.  The  pipe  is  then  covered 
with  soil  and  kept  wet  for  two  weeks. 

Twelve  men  will  easily  build  and  backfill  140  ft.  of  18-in.  pipe, 
100  ft.  of  24-in.  or  80  ft.  of  30-in.  pipe  in  a  day  of  nine  hours.  The 
company  is  replacing  30-in.  steel  pipe  under  40-ft.  head,  placed  on 
bridges,  with  concrete  siphons  of  the  same  size. 

Friction  Loss  in  Water  Pipes  and  Fittings 

The  method  of  test  upon  which  exponential  formulas  for  the 
friction  loss  of  head  of  water  flowing  through  standard  pipes  and 
fittings  were  based,  was  to  let  water  run  from  one  tank  to  another, 
with  and  without  the  given  pipes  and  fittings  in  the  connecting  line. 


Water  Works  87 

The  velocity  was  computed  after  calibrating  the  free  area  of  the 
pipe,  weighing  the  water  flowing  in  a  given  interval,  and  measuring 
the  difference  of  level  by  hook  gages.  In  this  way  the  head-velocity 
relations  were  established  for  various  velocities  in  pipes  of  i  to 
3  in.  nominal  size.  After  plotting  these  relations  on  double 
logarithmic  cross-section  paper  the  loss  per  foot  of  pipe  could  be 
secured.  Then  a  logarithimic  plot  was  made  of  values  of  K  in  the 
equation 

h  =  kip 

for  the  several  sizes  of  pipe.  From  these  the  final  formula  was 
deduced  as 

V1.75 

h  =  0.00685- 


'^1.275 

for  water  at  68°  F.  and  for  velocities  of  up  to  3  ft.  per  sec.,  in 
\-  to  3-in.  black  butt-welded  steel  pipe. 

Similar  studies  of  galvanized  pipes  gave  the  formula 

,,1.84 

h  =  0.00845^06 

In  general,  the  exponent  of  v  increases  with  the  interior  roughness 
of  the  pipe. 

Increasing  the  temperature  of  the  water  decreased  friction-head 
loss,  apparently  by  changing  the  coefficient  of  v  of  the  exponent. 
The  hot-water  experiments  were  not  completed. 

For  the  friction  loss  of  flow  at  68°  F.  through  one  standard 
short-radius  steam  elbow  the  formula  deduced  is 

.a.M 

h  =  O. 

Water-Sample   Shipping  Case 

A  shipping  case  holding  eight  4-oz.  water-sample  bottles  and 
having  an  ice  capacity  to  maintain  a  temperature  of  10°  C.  for  48 
hours  is  made  of  20-gage  galvanized  iron,  8  in.  wide,  15  in.  long 
and  13  in.  high  outside  dimensions.  It  is  insulated  with  1  in.  of 
pressed  corkboard  and  lined  with  24-gage  galvanized  iron,  which 
makes  a  water-tight  joint  with  the  outer  casing.  The  case  has 
two  covers:  (1)  An  insulated  cover,  which  has  a  tapered  edge  so 
it  will  drop  easily  into  place,  and  a  flange  to  support  it;  (2)  A 
protecting  cover  of  22-gage  galvanized  iron,  strengthened  at  the 
edge  with  wire,  and  provided  with  hinges  and  a  padlock  hasp.  The 
case  is  carried  by  means  of  a  rope  handle,  secured  to  strap  iron 


88  The  Engineer  in  Field  and  Office 

eyelets  riveted  to  the  sides  of  the  case.  The  container  for  the 
sample  bottles  is  a  can  5  in.  in  diameter  and  10  in.  high,  made  of 
26-gage  galvanized  iron,  and  provided  with  a  slip  cover  2-in.  deep. 
The  can  is  held  in  place  by  a  galvanized  iron  bond  attached  just 
above  midheight.  The  space  around  the  can  will  hold  13  Ib.  of  ice. 
If  desired,  a  liter  bottle  can  be  packed  in  the  can  instead  of  eight 
4-oz.  bottles. 

Hunting  Faults  in  Water  Mains 

For  the  last  few  years  the  Water  Department  of  the  City  of 
Baltimore  has  been  conducting  extensive  investigations  of  the 
condition  of  underground  structures  along  the  city  streets.  The 
object  is  twofold:  (1)  To  repair  leaks  and  save  water  and  (2)  to 
replace  old  and  weak  pipes  before  improved  pavements  are  laid. 

Formerly  the  method  was  to  tap  a  pipe  at  various  points  and 
with  pitot  tubes  measure  the  pressure  and  the  velocity  of  water 
flowing  and  thereby  the  volume.  With  all  house  connections  closed 
between  the  points  tapped  the  difference  between  the  volumes 
determined  by  the  pitot  tubes  gave  a  measure  of  the  leakage. 

It  is  now  the  custom  to  close  all  valves  on  a  section  of  pipe  to 
be  tested  and,  with  a  triplex  pump  attached  to  the  line,  to  subject 
it  to  a  water  pressure  of  300  Ib.  per  sq.in.  If  the  pipe  breaks,  it 
is  immediately  replaced,  thus  saving  the  expense  of  ripping  up 
improved  paving  a  few  years  hence  when  the  pipe  would  have 
eventually  broken.  A  measure  of  leakage  is  also  gained  by  this 
method  by  noting  the  drop  of  pressure  per  unit  of  time  in  the 
length  of  pipe  tested. 

A  Suggestion  for  Making  Water  Rates 

Compute  the  service  charge  by  adding  to  a  price  per  1,000  gal. 
or  100  cu.ft.,  first  X%  on  the  cost  of  the  meter  and  service  pipes 
where  owned  by  the  company,  then  Y%  on  the  cost  of  equipment 
required  to  meet  the  peak-load  demand  of  the  customer,  then  $Z 
for  meter  reading,  billing  and  collecting,  and  finally  $A  to  $#  for 
unregistered  water. 

The  reasons  for  such  a  suggested  procedure  need  little  exposition. 
There  are  two  kinds  of  water- works:  (1)  The  product-dispensing 
type,  which  pumps  at  a  small  steady  rate,  or  collects  as  nature 
furnishes,  and  delivers  out  of  adequate  storage  at  varying  rates; 
(2)  the  service  type,  which  maintains  pump  pressure  all  the  time 
and  has  power  apparatus  enough  to  meet  its  peak-load  demands. 
For  the  first  type  of  water  company  the  Y%  mentioned  above 


Water  Works 


89 


becomes  insignificant — even  disappears,  for  the  peak-load  equipment 
consists  only  of  a  possible  addition  to  diameter  of  mains,  and  even 
this  may  be  absorbed  in  the  provisions  for  fire  protection. 

Paying  attention  to  the  Y  percentage  in  the  case  of  the  service 
type  of  water-works  automatically  clears  away  much  of  the  worry 
about  manufacturers'  rates.  If  an  industrial  customer  does  not 
draw  during  peak-load  hours,  Y  may  disappear  so  that  an  attractive 
rate  can  be  made  to  him  that  will  still  render  a  respectable  profit 
to  the  water-works — or,  where  profits  are  not  sought,  at  least  make 
a  more  continuous  use  of  plant  and  increase  the  spread  of 
investment  charges.  This  would  be  a  development  parallel  to  the 
success  of  electric  central  stations  in  building  up  off-peak  commercial 
loads. 

Pressure  Constant  Under  Varying  Draft 

The  accompanying  charts  indicate  how  the  pressure  in  the  mains 
of  the  Passaic  water-supply  system  is  maintained  nearly  constant, 


Regulator  Valve  Holds  Pressure  Constant 

in  spite  of  the  varying  draft,  as  shown  in  the  second  chart.     The 
amount  delivered  varies  in  rate  of  draft  from  nothing  to  about 


90 


The  Engineer  in  Field  and  Office 


8,000,000   gal.   per   day.     As   may  be   seen   from   the   chart,   the 
variations  are  sudden  and  irregular. 

Water  is  taken  through  a  16-in.  regulating  valve.    The  upstream 
pressure  at  the  connection  is  about  100  Ib.  per  sq.in.;  it  is  reduced 


<b 


f  H  a  3  AV* 

Rate  of  Draft  Varies  from  0  to  About  8,000,000  Gal  per  day 

to  30  or  40  pounds.  Water  passing  through  the  regulator  valve  is 
taken  from  a  51-in.  main  and  delivered  to  a  30-in.  main.  The 
connection  was  installed  in  1908  and  has  been  operated  continuously 
and  satisfactorily  since  that  time. 

48-In.  Valve  Placed  on  Riser  Pipe 

The  large  elevated  water  tank  at  the  filtration  plant  of  the 
Louisville  Water  Co.,  Louisville,  Ky.,  was  originally  installed  without 
a  valve  between  the  48-in.  water-main  connection  and  the  52-in.  riser 
pipe.  The  steel  riser  pipe  recently  commenced  to  show  signs  of 
deterioration,  and  it  was  decided  to  put  in  a  valve  at  the  base  so  that 
the  riser  could  be  cut  out  for  repairs  without  interference  with  the 
connecting  mains. 


Water  Works 


91 


The  method  of  procedure  was  as  follows:     The  expansion- joint 
connection  at  the  cylindrical  bottom  of  the  tank  was  fixed  so  that 


Placing  48-Inch  Valve  in  Water-Tank  Riser  Pipe 

there  would  be  no  movement.  This  was  done  by  taking  out  every 
other  bolt  in  the  flange  connection  and  inserting  plates  of  steel 
which  would  completely  prevent  the  riser  pipe  from  moving. 

Large  Reservoir  to  be  Sealed  by  Sluicing 

What  is  probably  the  largest  task  of  reservoir-bottom  sealing 
ever  attempted  has  been  undertaken  by  Seattle,  Wash.  The  reservoir 
to  be  sealed  has  an  area  of  about  200  acres.  The  foundations  of  the 
dam  across  Cedar  River  which  forms  the  reservoir  are  on  bed-rock. 


92  The  Engineer  in  Field  and  Office 

However,  for  a  distance  of  over  a  mile,  the  north  bank  and  the  bed 
of  Cedar  River  show  a  considerable  leak,  which  appears  through 
4000  ft.  of  gravel  in  about  sixteen  days. 

Drilling  in  the  neighborhood  of  Cedar  Lake  has  shown  at  least 
8,000,000  cu.ft.  of  excellent  clay,  and  drilling  in  the  lake  itself  has 
shown  that  the  greater  part  of  the  material  on  which  it  rests  is 
blue  clay,  although  the  north  bank  of  the  lake  has  naturally  silted 
against  material  similar  to  that  which  is  now  to  be  treated.  The 
waters  of  Cedar  River  running  into  the  lake  are  absolutely  clear 
almost  the  entire  year,  and  at  such  times  as  they  are  not  clear  the 
silt  all  settles  in  the  lake  so  that  the  new  basin  cannot  seal  of  itself. 

A  pump  with  a  capacity  of  4000  gal.  per  min.  is  being  installed, 
and  this  is  to  be  connected  to  about  one  mile  of  16-in.  pipe,  which 
will  carry  the  water  to  an  elevation  of  approximately  350  ft.  for 
the  sluicing  out  of  the  clay  bed  which  has  recently  been  discovered. 
The  material  will  be  carried  over  grizzlies,  the  bars  of  which  will 
be  set  close,  as  only  the  fine  material  is  required.  This  will  be 
carried  back  to  the  north  bank  of  the  river  and  along  the  distance 
to  be  treated.  The  bank  is  steep,  and  a  considerable  amount  of 
material  has  to  be  sluiced  into  the  river  bottom  in  order  to  get 
the  proper  grade  for  silt  to  remain  on  the  surface.  The  water, 
with  clay  in  suspension,  under  the  350-ft.  head  above  mentioned,  will 
be  used  in  sluicing  the  gravel  from  the  bank  and  in  this  way  will  be 
incorporated  with  the  gravel  at  the  bank,  the  intention  being  to  use 
about  one  part  of  clay  to  three  or  four  parts  of  gravel.  The  first 
thousand  feet  next  to  the  new  dam  will  be  treated  first. 

The  present  rate  of  seepage  of  the  water  is  being  carefully 
measured  and  a  recording  gage  is  being  installed  which  will  give  the 
seepage  from  time  to  time  as  the  sealing  proceeds. 

Interesting  Solutions  of  Problems  in 
Sewer  Construction 

Two  Sewers  Laid  in  One  Trench 

Two  sewers  have  been  constructed  in  one  trench  in  Cambridge, 
Mass.,  since  1889,  ranging  in  a  great  variety  of  shapes  and  sizes 
from  a  storm  sewer  5  ft.  8  in.  by  6  ft.  over  an  8-in.  sanitary  sewer 
to  a  24-in.  storm  sewer  over  a  24  x  26-in.  sanitary  sewer. 

In  constructing  the  manhole  no  deflection  in  the  alignment  of 
the  upper  sewer  is  made,  as  the  manhole  is  built  to  keep  the  flow 
separate. and  yet  to  give  access  to  both  sewers  by  constructing  a 
removable  bottom  or  floor  slab  in  the  upper  chamber.  In  order  to 


Sewers 


93 


inspect  and  clean  the  lower  sewer,  it  is  necessary  only  to  tilt  up  the 
floor  slab  by  means  of  the  two-ring  bolts.  This  would  usually  be 
done  when  nothing  was  running  in  the  storm  sewer. 

The  drawing  shows  a  rather  interesting  example  of  this  type  of 
construction  on  account  of  the  unusual  distance  between  the  two 
sewers.  Ordinarily,  they  are  only  about  2  ft.  or  less  apart,  thus 


SBCT.ONAL  M_AN  OF  MANHOLE 


CROSS  -SECTION 

THROUGH  SEWER 


CROSS -SECTION 
THROUGH  MANHOLE 


No  Deflection  in  Alignment  at  Manholes 


reducing  the  depth  of  the  lower  chamber  and  increasing  the 
accessibility  of  the  lower  sewer.  This  style  of  "two-story"  manholes 
has  given  excellent  satisfaction,  being  convenient  as  well  as 
inexpensive. 

On  the  other  hand,  in  the  plans  for  the  sewerage  system  of  New 
Hartford,  N.  Y.,  the  storm-water  sewer  was  placed  below  the  grade 
of  the  sanitary  sewer,  and  with  porous  joints,  to  lower  the  ground 
water,  thus  enabling  easier  construction  of  the  sanitary  sewer  and 
greater  security  against  leakage,  for  the  joints  were  made  with 


94 


The  Engineer  in  Field  and  Office 


jute  and  cement.  For  good  foundation  the  sanitary  sewer  was  laid 
on  a  shelf  or  shoulder  cut  in  the  side  of  the  trench  made  for  the 
lower  sewer  after  that  was  laid  and  covered.  The  invert  of  the 
sanitary  sewer  was  at  the  same  elevation  as  the  top  of  the  other. 
Both  have  been  continuously  in  operation  and  without  trouble  of 
any  kind. 

Combined  Sanitary  and  Storm  Sewers 

The  proposed  sanitary  and  storm  trunk  sewers  at  Flint,  Mich., 
will  be  combined  in  one  structure  except  where  it  is  necessary  to 


Cross-Section  of  Storm  and  Sanitary  Sewers 

have  a  manhole  on  the  sanitary  portion.     At  such  intervals  the 
following  methods  are  used: 


Sewers 


95 


On  a  tangent  a  double  reverse  curve  of  100-ft.  radius  is  made 
in  the  storm-sewer  portion  only,  thus  separating  in  plan  the  two 
sewers  a  sufficient  distance  to  permit  the  building  of  a  manhole  over 
the  sanitary  sewer. 

At  all  angles  in  the  alignment  of  the  sewer  a  simple  curve  of 
50-ft.  radius  is  made  in  the  storm-sewer  portion  only.  The  sanitary 
sewer  is  carried  a  sufficient  distance  beyond  the  P.C.  and  P.T.  of 


Between 
Manholes 

How  Provision  Is  Made  for  Manholes 

the  storm  sewer  to  permit  the  building  of  two  manholes  on  the 
sanitary  sewer  in  case  the  deflection  angle  of  the  sewer  line  is 
betwen  45  and  90°,  and  one  manhole  in  case  the  deflection  angle  is 
45°  or  less. 

The  type  of  construction  proposed  for  that  portion  of  the  trunk 
line  in  which  it  becomes  necessary  to  separate  in  profile  the  two 
sewers  is  illustrated.  The  maximum  depth  of  sewer  is  33  ft.,  and  the 
minimum  depth  is  15  feet. 

Calk  Sewer  Joints  Under  Some  Conditions 

Many  engineers  continue  to  construct  storm  sewers  with  open 
joints,  basing  their  practice  on  the  theory  that  the  sewer  is  to 
remove  surface  water  and  that  there  is  a  further  advantage  gained 
by  allowing  all  the  water  possible  to  enter  the  sewer  by  seepage 
through  the  open  joints. 

For  some  time  the  City  of  Cadillac  has  experienced  difficulty 
in  discharging  the  storm  water  through  a  24-in.  sewer  that  carries 
the  surface  water  from  a  portion  of  the  city.  Several  had  "satisfied" 
themselves  that  it  was  being  blocked  by  the  accumulation  of  tar  from 
the  local  gas  plant,  which  discharged  its  waste  water  near  this 
point.  A  thorough  investigation  made  during  the  past  winter  showed 


96 


The  Engineer  in  Field  and  Office 


the  necessity  of  digging  up  the  sewer.  A  profile  taken  of  the  sewer 
as  found  indicated  that  there  was  a  vertical  settlement  of  4.79  ft.  at 
a  distance  of  40  ft.  from  the  manhole  on  an  intersecting  street.  No 
variation  horizontally  was  noted. 

The  sewer  was  laid  on  a  small  grade  through  low  sandy  soil. 
Due  to  the  fact  that  it  received  a  large  amount  of  water  during 
storms  and  spring  thaws,  there  was  a  head  of  water  sufficient  to 
force  through  the  open  joints.  The  intermittent  rise  and  fall  of 
water  surrounding  the  pipe  washed  sand  through  the  open  joints 


Open  Joints  Caused  This  Sewer  to  Settle 

into  the  sewer.  This  process,  continued  for  a  period  of  years,  has 
caused  the  pipe  to  settle,  thereby  increasing  the  openings  in  the 
joints  and  completely  undermining  the  sewer  until  it  had  settled 
more  than  two  and  one-third  times  its  diameter. 

Some  lengths  of  the  pipe  were  nearly  filled  with  sand,  but  no 
evidence  of  an  accumulation  of  tar  was  found.  Most  of  the  pipe 
was  removed  from  the  trench  and  relaid  with  joints  calked  with 
oakum  and  filled  with  cement  mortar. 

Measuring,  Locating  and  Stopping  Sewer  Leaks 

When  the  sewer  system  built  for  Bakersfield,  Calif.,  in  1913-14 
was  completed,  one  line,  comprising  about  6600  ft.  of  10-,  12-  and 
14-in.  vitrified  pipe,  was  found  to  be  leaking  badly.  This  line  is 
located  in  low,  flat  ground,  and  the  sewer,  throughout  most  of  its 
length,  is  covered  by  groundwater  to  a  depth  varying  with  the 
seasons  of  the  year.  The  exact  amount  of  leakage  into  the  line  was 
readily  determined,  owing  to  the  fact  that  this  sewer  empties  into 
a  concrete-lined  reservoir,  from  which  the  sewage  is  pumped  to  a 
gravity  outfall  sewer. 

SERIES  OF  LEAKAGE  MEASUREMENTS  MADE 

From'  measurements  extending  over  a  period  of  24  hours  in 
February,  1914,  it  was  found  that  the  leakage  amounted  to  70,500 


Sewers  97 

gal.  in  24  hours.  At  the  time  of  this  test,  the  groundwater  was 
probably  slightly  above  the  mean  stage.  On  Oct.  13,  1914,  with  the 
groundwater  near  its  lowest  level,  the  leakage  was  39,075  gal.  in 
24  hours.  From  observations  on  the  level  of  the  groundwater  at 
various  points  along  the  line  of  the  sewer  it  was  determined  that 
infiltration  was  taking  place  at  an  average  rate  of  6.83  gal.  per 
lin.ft.  of  submerged  joint. 

On  May  11  and  12,  1915,  a  similar  test  was  made.  It  was 
estimated  that  the  top  of  the  pipe  was  covered  to  an  average  depth 
of  3  in.  throughout  its  whole  length.  The  flow  at  this  time  amounted 
to  over  121,000  gal.  in  24  hours,  giving  a  leakage  of  15  gal.  per  lin.ft. 
of  joint  in  24  hours. 

The  method  of  repairing  was  as  follows:  First,  the  trench  was 
opened  and  the  pipe  uncovered  down  to  about  its  middle.  The  soil 
was  then  scooped  out  entirely  around  the  pipe  at  each  joint,  leaving 
a  series  of  oval-shaped  depressions  beneath  the  pipe.  In  the  majority 
of  instances  the  groundwater  was  at  such  a  height  that  the 
depressions  beneath  the  joints  were  only  partly  filled  with  water. 
In  other  cases  the  groundwater  was  high  enough  to  render  pumping 
necessary,  certain  portions  of  the  line  being  entirely  covered  by 
water.  As  the  soil  at  the  depth  of  the  pipe  was  almost  pure  sand, 
the  flow  of  water  into  the  trench  was  very  great,  and  sheeting 
had  to  be  done  with  considerable  care.  For  the  most  part,  ordinary 
2-in.  pine  lumber  was  used. 

After  the  joints  for  a  distance  of  one  block  were  exposed  as 
described  (or  for  a  less  distance  when  pumping  was  required),  the 
pipe  was  tightly  plugged  in  the  manhole  at  the  lower  end  of  the 
block.  Water  was  then  introduced  into  the  pipe  above  and  allowed 
to  flow  down  until  the  block  of  uncovered  pipe  was  entirely  filled. 
During  the  filling  of  the  pipe  a  man  was  stationed  in  the  manhole 
at  the  upper  end  of  the  block.  As  the  stream  flowed  past  him,  he 
slowly  sprinkled  red  aniline  dye  into  the  water,  which  was  thus 
colored  a  bright  red.  This  water,  trickling  into  the  little  pools 
below  the  joints,  revealed  all  the  leaks,  even  the  very  small  ones. 
The  defective  joints  were  marked  as  found,  after  which  the  pipe  was 
emptied  and  the  trench  allowed  to  drain  if,  as  was  frequently  the 
case,  it  became  partly  filled  by  the  leakage  from  the  pipe. 

The  defective  joints  were  then  carefully  cleaned,  and  a  thick 
collar  of  rich  cement  mortar  was  applied  directly  over  the  old  joint. 
A  strip  of  muslin  about  9  in.  wide  was  tied  snugly  over  the  cement 
collar  to  prevent  its  falling  away  from  the  pipe  or  being  washed 


98  The  Engineer  in  Field  and  Office 

out  of  the  joint  by  groundwater.  It  was  found  that  fresh  joints 
protected  by  this  means  were  not  injured  by  exposure  to  water 
where  there  was  no  current.  Where  water  came  into  the  trench  in 
a  quantity  sufficient  to  make  an  appreciable  current,  no  chances 
were  taken,  and  it  was  kept  down  by  pumping. 

After  the  cement  mortar  had  had  time  to  set  hard,  the  pipe  was 
again  filled  with  water,  colored  as  before,  and  any  leaks  remaining 
were  repaired  and  the  trench  backfilled.  After  the  repair  of  the 
line  was  completed,  several  measurements  of  the  infiltration  were 
taken.  A  comparison  of  the  infiltration  before  and  after  the  repair 
may  be  interesting: 

Estimated  Rate  per 

Total  Leakage,  Lin.Ft.   of  Joint 

DATE                                         Gal.  Submerged,  per  24  Hr. 
Before  Repairing: 

Oct.     13,1914 39,075  9.6 

May    12,  1915 121,000  15.0 

After  Repairing: 

Dec.  29,  1915,  to  Jan.  10,  1916,  12  days           1,200   per  day                     0.3 

Feb.    10,  1916 12,000  1.5 

Zinc  Balls  Clean  Sewers 

Some  years  ago  a  pipe  sewer  system  was  constructed  in 
Owensboro,  Ky.  It  was  stipulated  in  the  specifications  that  a  ball 
2  in.  smaller  than  the  bore  of  the  pipe  should  pass  through  without 
lodging.  In  making  this  test  on  a  certain  section  of  sewer,  the  ball 
became  lodged  and  had  to  be  flushed  to  the  manhole  below.  When 
the  ball  appeared  in  the  manhole,  it  was  found  carrying  a  half  brick 
before  it.  Appreciating  the  significance  of  this  accidental  discovery, 


FLOW 


4 


How  the  Ball  and  Water  Clean  the  Sewer 

this  principle  was  applied  to  the  cleaning  of  sewers.  The  writer 
for  a  number  of  years  has  used  this  method  with  excellent  results. 
It  is  not  successful  where  roots  are  encountered,  but  where  silt  and 
debris  have  collected  in  the  sewer — due  to  the  absence  of  flush  tanks 
and  catchbasins,  or  where  the  latter  have  been  allowed  to  fill — this 
plan  has  been  found  to  be  cheaper  than  the  drag  or  bucket  method 
and  entirely  satisfactory. 


Sewers 


When  a  sewer  is  flushed  without  a  ball  ahead  of  the  stream  of 
water,  the  sand  or  silt  is  pushed  forward  by  the  flow  of  water  and 
the  outlet  is  choked,  thereby  causing  the  water  to  back  up  and  so 
lose  its  nozzle  pressure  ;  when  a  ball  is  used  ahead  of  the  water,  the 
outlet  is  kept  partly  open,  thus  utilizing  the  pressure. 

If  the  sewer  is  badly  choked,  a  ball  5  to  10  in.  smaller  than 
the  diameter  of  the  pipe  is  placed  in  the  sewer  at  the  manhole  and 
a  stream  of  water  applied  behind  the  ball  until  it  appears  at  the 
manhole  below;  the  deposit  is  removed  from  the  manhole,  and  a 
larger  ball  is  then  started  from  the  manhole  above  and  carried 
through  as  before.  This  plan  is  repeated  until  the  sewer  is  clean. 
To  insure  a  clean  sewer,  the  last  ball  to  pass  through  should  be  2  in. 
smaller  than  the  sewer.  Where  sewers  are  not  badly  choked,  the 
first  ball  may  be  large,  the  size  depending  on  the  condition  of  the 
sewer.  The  ball  should  float  and  should  be  as  light  as  is  consistent 
with  strength.  Those  used  with  best  results  are  hollow  and  made  of 
two  thicknesses  of  No.  24  gage  zinc,  the  seams  being  set  at  right 
angles.  The  sizes  run  from  4  to  22  in.  Wooden  balls  have  not 
proved  satisfactory. 

A  fork  or  screen  with  a  sandbag  directly  in  front  of  it  should  be 
placed  at  the  inlet  end  of  the  lower  manhole.  This  is  to  prevent  the 
ball,  together  with  the  silt  expelled  from  the  cleaned  sewer,  from 
escaping  into  the  next  section  of  sewer.  A  line  of  sewer  should 
of  course  be  cleaned  in  sections,  beginning  at  the  upper  manhole. 

Last  year  an  abandoned  sewer  of  15-in.  diameter  was  found  to 
be  almost  filled  with  silt,  there  being  a  space  of  about  2  in.  only  at 
the  top  to  allow  passage  of  water.  In  cleaning  this  a  4-in.  ball 
was  first,  and  last  a  13-in.  ball.  With  the  aid  of  these  balls,  5  cu.yd. 
of  sand  was  removed  from  this  sewer  in  four  hours. 

River  Outlet  for  Combined  Sewers 

In  connection  with  a  recently  published  report  on  sewerage 
improvements  at  Davenport,  Iowa,  a  sketch  for  typical  outlets  to 
the  Mississippi  River  was  included  which  is  reproduced  herewith. 
The  general  scheme  is  sewage  disposal  by  dilution.  Where  the 
inverts  of  the  mouths  of  the  various  outlet  sewers  would  be  above 
ordinary  water  level  a  run  of  cast-iron  pipe  would  take  the 
dry-weather  sewage  to  a  submerged  outlet.  Where  submerged 
dry-weather  flow  outlets  are  impracticable,  vertical  bar  screens 


100 


The  Engineer  in  Field  and  Office 


might  be  installed   in  the  future;   but  these  are   to  be  avoided 
where  and   as   long   as  possible   on   account   of   the   trouble   and 


Ordinary 


Securely  anchored 
Mtssissippr  MVE* 


•••Shore  Line 


Proposed  River  Outlet  for  Sewage  Disposal  by  Dilution 
at  Davenport,  Iowa 

expense   of   cleaning  the   screens.     It   is   thought   that   complete 
disposal  by  dilution  will  be  practicable  at  most  of  the  outlets. 

What  Engineers  are  Doing  in  the  Fields  of  Flood 
Control,  Irrigation  and  Hydraulics 

Design  of  Flood-Retarding  Reservoirs 

A  problem  often  encountered  in  flood-prevention  studies  is  to 
determine  how  the  flood  flow  of  a  stream  will  be  affected  by  the 
construction  of  a  retarding  reservoir.  The  nature  of  this  problem 
and  the  usual  method  of  solving  it  have  been  stated  as  follows: 
The  rate  of  outflow  from  the  basin  in  a  flood  depends  on  the 
height  to  which  the  basin  is  flooded.  This  height  in  turn  depends 
on  the  volume  stored,  which  is  the  difference  between  the  inflow 
and  the  outflow.  Thus  the  quantities  involved  are  inter-related. 
The  problem  of  computing  the  outflow  had  to  be  solved  by  trial 
and  error.  This  method  of  working  is  inconvenient  and  laborious. 
It  may  be  avoided  by  the  use  of  the  solution  given  below. 

Notation:  t  =  any  short  interval  of  time  during  the  flood; 
o  =  rate  of  outflow  from  reservoir  at  any  instant,  or  during 
interval  t;  O  =  total  or  accumulated  outflow  up  to  the  beginning 
of  interval  t;  S  —  total  quantity  of  water  stored  in  reservoir  at 
any  instant,  or  at  the  middle  of  interval  t. 

Given:  (a)  The  original  time-flow  curve  or  flood-hydrograph 
of  the  stream,  giving  the  rate  of  inflow  into  the  proposed  reservoir 


Irrigation  and  Hydraulics 


at  each  instant  during  the  flood  considered,  (b)  The  depth-storage 
curve  of  the  reservoir,  giving  the  total  quantity  S  of  the  water 
stored  in  the  reservoir  when  the  surface  is  at  any  given  elevation, 
(c)  The  depth-outflow  curve  of  the  reservoir,  giving  the  rate  o 
of  the  outflow  from  the  reservoir  when  the  water  surface  is  at 
any  given  elevation.  This  curve  will  be  approximately  parabolic 
if  the  outlet  is  a  tunnel. 

Required:  The  new  time-flow  curve  for  the  stream  as  modified 
by  the  proposed  reservoir,  giving  the  rate  o  of  the  outflow  which 
would  pass  from  the  reservoir  during  each  instant  of  the  flood 
considered. 

Solution:  From  the  original  time-flow  curve  of  the  stream  plot 
a  curve  of  accumulated  inflow  at  successive  instants  during  the 
flood.  This  curve  is  the  "mass  curve"  for  the  stream  during  the 
flood  considered.  Erect  ordinates  to  this  curve,  spaced  at  a  uniform 
time  interval  I  so  small  that  the  curve  will  not  vary  sensibly  from 
a  straight  line  between  ordinates. 

Using  the  depth-storage  and  depth-outflow  curves,  construct  a 
storage-outflow  curve  for  the  reservoir  and  on  the  same  sheet 
construct  another  curve  whose  ordinate  corresponding  to  any  outflow 
o  is  S  %ot- 


Outflow  Rate 


Storage-Outflow  Curve  Can  Be  Plotted  from  Accumulated- 
Flow  Curves 


If  the  accumulated  outflow  O  is  given  at  the  beginning  of  any 
time  interval  t,  the  outflow  curve  may  be  extended  through  that 
time  interval  without  the  use  of  trial  and  error  methods  by  taking 
from  the  first  curve  the  outflow  rate  o  corresponding  to  the  value 
of  the  quantity  S  +  \ot  as  scaled  from  the  middle  of  the  time 
interval  t  in  Fig.  1,  and  multiplying  this  rate  by  t  to  obtain  the 
outflow  ot  during  the  interval.  The  method  applies  without  change 


•  ^e    ?  C^  V  D*>" 

i     a  A  ft  -^  ^i^n 

"^  ;    ;;  The  Engineer  in  Field  and  Office 

to  the  first  time  interval  of  the  flood  where  O  is  zero.  The 
operations  may  be  carried  out  in  tabular  form  if  desired,  without 
drawing  the  curves. 

When  the  accumulated-outflow  curve  has  been  completed  in  the 
manner  described,  the  desired  outflow  hydrograph  of  the  stream  may 
be  readily  obtained  from  it. 

Small  Wells  Help  Drain  Irrigated  Land 

Rising  wells  or  boreholes  sunk  below  the  level  of  tile  drains 
may  materially  assist  the  drainage  of  irrigated  lands  that  are 
underlain  by  shale.  This  applies  particularly  to  such  lands  in 
the  Rocky  Mountain  States,  where  the  water  in  the  shale  is  under 
pressure  and  where  methods  employed  in  other  sections  of  the 
country  have  not  proved  successful.  Deep  tile  drains  are  required, 
not  less  than  6  ft.,  and  as  much  as  8  ft.  deep  in  many  cases.  The 
depth  to  the  water-carrying  strata,  however,  is  much  too  great  for 
ditching;  and  as  pressure  conditions  exist  in  these  strata,  the 
sinking  of  wells  permits  the  water  to  rise  into  the  drains. 

Owing  to  the  character  of  flow  in  shale  ground,  the  area  of 
influence  of  a  relief  well  is  not  large,  and  from  two  to  six  wells 
per  100  ft.  of  trench  may  be  necessary.  Their  maximum  depth 
is  usually  20  ft.  below  the  drains,  and  in  general  the  flow  is 
encountered  at  a  depth  of  about  15  ft.  In  most  cases  a  2-in.  hole 
is  sufficient  to  care  for  the  water. 

The  well  should  be  located  near  the  end  of  a  tile,  and  one 
end  of  the  tile  then  chipped  so  as  to  leave  a  2-in.  hole  over  the 
well.  If  the  banks  will  not  stand  and  the  wells  must  be  driven 
as  the  tile-laying  progresses,  the  well  should  be  a  few  inches  to 
one  side  of  the  drain  and  connected  to  the  hole  in  the  latter 
by  placing  a  half -tile  over  the  well.  If  the  well  is  directly  under 
the  tile,  it  is  likely  to  be  closed  by  sediment  washing  into  it, 
especially  if  the  flow  is  weak. 

Modified  Pitot  Gives  High  Accuracy 

The  pitot  tube  has  long  been  used  as  a  device  for  measuring 
the  flow  of  liquids  and  gases,  but  only  when  used  with  the  utmost 
care  have  the  results  proved  uniform.  Many  experimenters  have 
worked  with  modified  forms  in  the  endeavor  to  reduce  the  variation 
in  results,  but  it  is  evident  not  only  that  the  data  obtained  are 
variable  in  the  hands  of  different  men,  but  that  the  same  tube 
may  have  different  coefficients. 


Irrigation  and  Hydraulics 


103 


In  order  to  correct  this  latter  defect  the  "Hydraulic  Shunt-Flow 
Tube,"  was  devised.  This  device  is  a  tube  so  arranged  that  it 
may  be  introduced  into  the  stream  with  the  tip  directed  against 
the  flow  and  yet  maintain  at  the  tip  the  same  pressure  that 
existed  before  the  introduction  of  the  tube.  The  water  flows  into 
this  tube  and  may  be  shunted  into  a  small  container  and  weighed, 
leaving  the  velocity  undisturbed  from  the  normal. 


Valve 


Common'  Pitot  Tube 
FIG.  I 

Formula: 

V' 

H*  Pitot  Head. 
C  •    »  Coefficeni- 
a  »  Acceleration  of  Gravity 


Hydraulic    Shun* 
(Modification  of  tfie  Pilot  Tube) 

Formula:       FIG.  2 


Q*  flow  from  Tube 
A  *  Area  pf  lip  Opening 
(  •  Tip  Coefficient 


Almost  as  Simple  as  a  Pilot  Tube 

The  velocity  of  flow  at  the  tip  of  the  tube  will  be  equal  to  the 
quantity  of  water  collected  in  the  measuring  tank,  in  a  measured 
time,  divided  by  the  area  of  the  tip — all  quantities  being  measured 
in  the  usual  units.  It  is  possible  to  demonstrate  mathematically 
that  turbulent  flow  should  not  affect  the  coefficient  of  the  tip. 
Theoretically,  of  course,  the  tip  coefficient  should  be  unity  under 
all  conditions,  but  a  series  of  experiments  undertaken  with  this 
in  view  show  that  it  varies  less  than  1% — the  pitot  coefficient  under 
like  condition  varying  more  than  4%. 


Dams  of  Boulder-Filled  Wire  Baskets 

Two  hydraulic  dams  recently  built  in  California  consist  of  units, 
or  baskets,  of  poultry  netting  filled  with  coarse  gravel  and  rock 
These  units  are  built  in  place  and  are  laid  like  shingles  on  a  roof. 
Into  the  netting  are  passed  very  coarse  gravel  and  rock  up  to  the  size 
of  a  man's  head.  When  a  sufficient  quantity  has  been  deposited,  the 
top  is  leveled  off  with  a  straightedge,  and  the  selvage  edges  of  the 


104    ."."•';  The  Engineer  in  Field  and  Office 

netting  are  drawn  together  by  means  of  a  piece  of  strap  iron  with  a 
hooked  end.  The  selvage  edges  are  then  fastened  together  with 
wire,  and  the  ends  are  folded  in  and  similarly  fastened. 

Discharge  Plotted  with  Novel  Curve 

A  quick  and  easy  method  has  been  developed  for  showing  the 
variations  in  quantity  of  water  passing  a  given  point  in  a  stream. 

The  common  method  of  obtaining  a  continuous  chronological 
record  of  the  fluctuations  of  the  height  of  water  in  rivers  is  by 
means  of  a  gage  with  a  clock  and  float  attachment.  This  curve  is 
used  in  connection  with  what  is  known  as  a  "station-rating  curve" 
to  determine  the  amounts  of  discharge.  The  usual  method  of  plot- 
ting a  discharge  curve  is  by  reading  from  the  station-rating  curve 
the  quantities  corresponding  to  critical  points  on  the  curve  of  gage 
heights  and  then  plotting  these  results  against  time  on  a  separate 
sheet  of  cross-section  paper. 

The  method  herein  described  permits  plotting  the  discharge 
curve  on  the  same  paper  with  the  curve  of  gage  heights.  It  also 
eliminates  the  time  consumed  in  reading  the  gage  heights,  then 
referring  to  the  station-rating  curve  to  obtain  the  discharge,  and 
finally  plotting  that  value.  This  method  presupposes  the  use  of 
cross-section  paper  on  the  recording  gage,  as  is  usual  with  those 
gages  which  have  a  rectilinear  rather  than  a  circular  movement 
of  the  recording  pencil. 

It  is  necessary,  first,  to  plot  the  station-rating  curve  with  the 
same  scale  of  heights  as  is  found  on  the  gage-height  record.  Then 
draw  a  straight  line  from  the  origin  at  an  angle  of  45°  with  the 
axes.  Next,  cut  out  with  a  sharp  knife  the  sections  lying  between 
the  station-rating  curve  and  this  45°  line.  Finally,  paste  a  piece 
of  cardboard  at  the  bottom  of  this  curve,  keeping  the  lower  edge 
straight  and  parallel  to  the  horizontal  axes. 

This  station-rating  curve  is  then  superimposed  on  the  gage- 
height  record  so  that  the  horizontal  lines  representing  the  same 
gage  height  coincide.  A  scale  of  quantities  precisely  like  that  on 
the  station-rating  curve  is  then  laid  off  on  the  vertical  axis  of  the 
gage-height  curve,  the  zero  of  this  scale  starting  at  the  origin  of  the 
station-rating  curve.  To  plot  the  discharge  curve,  all  that  is  now 
necessary  is  to  move  the  station-rating  curve  horizontally  along  a 
straight-edge  until  it  intersects  the  curve  of  gage  heights  at  any 
point  A.  Then  follow  the  vertical  from  this  point  until  it  in- 


Irrigation  and  Hydraulics 


105 


tersects  the  45°  line.  This 
intersection  A'  is  a  point 
on  the  discharge  curve. 

Repeat  this  operation 
for  all  critical  points  A 
and  then  connect  the  points 
A'  with  a  smooth,  free- 
hand curve.  This  gives  the 
discharge  curve  as  in  Fig. 
1  plotted  on  the  same  paper 
with  the  gage-height  rec- 
ord and  corresponding  to 
the  time  scale  thereon.  To 
determine  the  total  dis- 
charge, planimeter  the  area 
under  the  discharge  curve 
thus  plotted. 

That  this  method  is  cor- 
rect is  due  to  the  selection 
and  arrangement  of  the 
scales  of  height  and  quan- 
tity and  to  the  fact  that  the 
ordinate  of  any  point  on  a 
straight  line  passing 
through  the  origin  and 
making  an  angle  of  45° 
with  the  axes  equals  its 
abscissa.  The  operation  of 
this  method  of  plotting  will 
be  facilitated  if  the  sta- 
tion-rating curve  is  made 
on  tracing  cloth  and  with 
no  vertical  or  horizontal 
lines  except  the  axes.  The 
little  extra  time  required  in 
the  preparation  of  the  sta- 
tion-rating curve  is  many 
times  recovered  when  plot- 
ting the  discharge  curve, 
especially  if,  as  is  often  the 
case,  the  gage-height  curve 
extends  over  a  long  period 
of  time. 


106  The  Engineer  in  Field  and  Office 

Movable   Flume  on  Hydraulic   Fill  Dam 

During  the  construction  of  a  large  hydraulic  fill  dam  recently 
completed  in  the  West,  considerable  time  was  saved  by  the  use  of 
an  inclined  runway  for  the  flume  from  which  material  was  deposited 
on  the  dam.  Although  the  flume  was  moved  by  hand,  it  was  only 
necessary  to  interrupt  the  flow  for  short  periods  while  the  delivery 
flume  was  skidded  along  the  incline  to  the  desired  new  position. 

Three  borrow  pits  were  used,  from  which,  by  means  of  hydraulic 
giants,  material  was  sluiced  into  three  main  flume  lines.  From  these 
mains  the  material  was  conveyed  through  flumes  along  the  upstream 
and  downstream  sides  of  the  fill.  By  the  use  of  gates  the  streams 
were  discharged  from  the  flumes  at  the  desired  intervals  toward  the 
axis  of  the  dam. 

The  flume  box,  12  x  24  in.  in  section,  was  built  up  of  li-in.  boards 
and  was  paved  with  6  x  12  x  6-in.  hemlock  blocks  set  on  end.  Im- 
mediately above  the  blocks  1  x  6-in.  projecting  strips  were  nailed  on 
either  side.  This  box  was  supported  on  2  x  6-in.  stringers,  which 
in  turn  were  carried  by  4  x  6-in.  caps  on  the  low  sliding  bents  spaced 
15  ft.  apart  and  inclined  on  a  slope  of  5  to  1.  The  6  x  6-in.  inclined 
caps  were  supported  on  pieces  of  the  same  size  resting  on  the  ma- 
terial previously  deposited  and  tied  together  by  cross-bracing. 

The  flume  proper  was  moved  up  the  incline  by  means  of  a  lever 
and  chain  device  at  each  bent.  The  lever  consisted  of  an  iron  bar 
near  the  lower  end  of  which  was  fastened  a  chain  connecting  with 
the  framing  of  the  flume  box.  At  the  extreme  lower  end  of  the  bar 
a  second  chain  was  attached  which  passed  over  an  iron  claw  fastened 
to  the  upper  end  of  the  inclined  6  x  6-in.  cap.  This  lever  was 
operated  by  one  man  at  each  bent.  With  the  lever  in  an  upright 
position,  pulling  it  down  through  the  quadrant,  which  it  was  possible 
to  describe,  would  move  the  flume  up  the  incline  a  few  inches.  This 
gain  was  then  caught  by  taking  up  slack  in  the  chain  at  the  claw, 
and  the  operation  repeated. 

Short  lengths  of  lateral  flumes  were  attached  to  the  openings  in 
the  upstream  side  of  the  flume  box  to  facilitate  control  of  the  flow. 
Doors  for  closing  the  openings  were  provided  so  that  material  could 
be  discharged  at  any  desired  point  along  the  crest  of  the  fill,  a 
duplicate  line  of  flume  being  used  along  up  and  down  stream  faces. 
Of  course  each  time  the  flume  was  moved  it  was  necessary  to 
establish  a  new  connection  at  the  point  where  it  was  fed  from  the 
supply  flume.  Sluicing  was  carried  on  practically  continuously  night 
and  day  in  order  to  save  time,  and  the  movable  feature  of  the  flume 
was  considered  to  be  a  factor  in  the  progress  made  on  the  job. 


Railway  Civil  Engineering 


107 


Hydraulic  Elements  of  Semicircular  Flume 

The  accompanying  curves  give  the  hydraulic  elements  of 
semicircular  flumes,  partly  full,  in  simpler  form  than  curves  before 
published.  They  can  be  platted  in  a  few  minutes  from  the  elements 


UVl' 

01016 
0.015 
0.014. 
0.013 
0.012 
0.011 

6o.oio 

Z  0.009 
E0.008 
C0.007 

\ 

\ 

\ 

V 

\ 

\ 

\ 

\ 

t* 

r  = 

AREA  OF  WETTED  SE6M 
SQ 
HYDRAULIC  RADIUS,  FT. 
FLUME  NUMBER 

ENT 
FT 

\ 

\ 

\ 

\ 

"" 

\ 

\ 

,  1 

\ 

Vs 

z. 

& 

" 

S 

\ 

0.005 
0.004 
C.003 
0.002 
<MX>1 

°c 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

Z  03  0.4  05  OJ6  0.7  05  0.9   LO    U    tfc    13    U  15  16 

Curves  for  Semicircular-Flume  Computations 

of  circular  segments  of  radius  unity,  tabulated  in  almost  any  book 
dealing  with  the  flow  in  circular  conduits,  by  using  the  commercial 
number  of  the  flume,  which  is  the  length  of  the  curved  flume  sheet 
in  inches,  instead  of  the  diameter.  The  wetted  perimeter,  which 
is  seldom  used,  can  be  easily  found  from  the  area,  and  the  hydraulic 
radius  or  the  curve  can  be  drawn  if  desired. 

Practical  Pointers  for  Railway  Civil  Engineers 

Accurate  Stadia  Profile  at  Low  Cost 

A  stadia  profile  was  run  last  summer  over  the  Illinois  Central 
R.R.  from  Champaign  to  Centralia,  111.,  a  distance  of  125  miles,  for 
the  railway-engineering  department  of  the  University  of  Illinois. 
Top-of-rail  elevations  were  desired  at  intervals  of  300  ft.  for  use  in 
connection  with  grade-resistance  investigations.  The  requirements 
that  the  stations  should  be  tied-in  to  the  mile  posts  and  that  the 


108 


The  Engineer  in  Field  and  Office 


linear  error  in  any  mile  should  be  not  more  than  10  ft.,  which  is  as 
close  as  the  mile  posts  can  be  indicated  on  the  dynamometer-car 
charts,  were  easily  met. 

Using  300-ft.  sights,  there  would  be  18  readings  to  each  mile; 
hence,  assuming  an  accuracy  in  the  stadia  readings  of  1  in  300,  the 
probable  error  in  the  length  of  a  mile,  according  to  the  method  of 
least  squares,  would  be  1/18,  or  4.35  ft.,  which  is  well  within  the 
allowable  limit  of  error.  This  made  it  possible  to  use  the  stadia 
instead  of  the  usual  method  of  chaining. 

In  starting  the  work  the  rodman  held  the  rod  on  the  top  of  the 
rail  opposite  a  mile  post,  and  this  point  was  recorded  as  Sta.  0.  The 
levelman  then  paced  a  distance  of  300  ft.  and  took  a  stadia  reading 


K)      20     JO     4O      50      60      70      SO     9O     100    HO     120    150 

MILES 
Compensating  Tendency  in  Linear  Errors  of  Stadia 

with  the  instrument  only  approximately  level.  If  the  paced  distance 
was  within  5  ft.  of  that  indicated  by  the  stadia  sight,  the  instrument 
was  finally  leveled,  and  accurate  level  and  stadia  readings  were 
taken.  Any  error  in  excess  of  5  ft.  was  corrected  by  making  a  new 
set-up.  The  rodman  then  advanced  to  Sta.  3,  approximately  opposite 
the  instrument,  and  a  level  reading  was  taken. 

The  rodman  then  paced  300  ft.  in  advance  and  gave  the  levelman 
a  trial  reading  for  distance.  The  levelman  signaled  the  correction 
necessary  to  locate  Sta.  6,  which  point  was  marked  on  the  rail  with 
keel  and  used  as  a  turning  point.  The  process  was  repeated  at 
distances  of  300  ft.  until  Sta.  48  was  reached.  The  instrument  was 
set  up  as  nearly  midway  between  Sta.  48  and  the  mile  post  as  could 
be  determined  by  eye.  Readings  to  Sta.  48  and  to  the  mile  post  were 
made  and  added  to  the  distance  previously  covered.  In  this  way  the 
distances  between  mile  posts  for  122  of  the  125  miles  were  obtained. 


Railway  Civil  Engineering  109 

The  distances  between  mile  posts  as  given  on  the  Illinois 
Central's  official  profile  were  assumed  to  be  correct,  and  the  differ- 
ences between  these  distances  and  those  obtained  by  stadia  meas- 
urements were  considered  the  errors  in  the  stadia  measurements.  In 
very  few  instances  were  the  mile  posts  5280  ft.  apart,  as  indicated 
by  the  railroad  chaining.  The  distances  between  posts  varied  from 
5265  to  5285  ft.;  hence,  not  knowing  what  reading  to  expect,  the 
observer  was  entirely  unbiased  in  taking  the  last  reading  in  each 
mile.  In  every  case  the  stadia  measurement  was  made  and  recorded 
before  the  chained  value  was  taken  from  the  profile. 

The  maximum  error  in  any  one  mile  was  14  ft.  In  7  miles  there 
was  no  error;  in  67%  of  the  miles  the  error  was  5  ft.  or  less;  in  96% 
it  was  10  ft.  or  less,  and  the  average  error  per  mile  was  only  4.5  ft. — 
conforming  closely  to  the  probable  error  of  4.35  ft.  expected  accord- 
ing to  the  method  of  least  squares. 

As  some  of  the  errors  were  plus  and  some  were  minus,  the 
accumulated  error  at  no  point  was  very  large.  The  total  error  at 
the  end  of  each  mile  has  been  plotted  in  the  accompanying  curve, 
and  it  is  seen  (1)  that  the  largest  error  was  60  ft.  at  the  end  of 
the  fiftieth  mile,  (2)  that  the  error  at  the  end  of  the  one  hundred  and 
twenty-second  mile  was  12  ft.,  and  (3)  that  at  eight  points  along 
the  line  it  was  zero. 

Laying  Out  Crossovers  Between  Curved  Tracks 

Crossovers  between  non-parallel  curved  tracks  can  hardly  be 
located  by  any  exact  mathematical  formula.  Cut-and-try  methods 
on  paper  on  a  large  scale  are  the  main  recourse;  but  it  is  very 
difficult  to  lay  out  the  flat  curves  without  resort  to  geometrical  con- 
struction, the  lines  of  which  would  cover  the  paper  if  many  trials 

Offset- Scats   \  Frocr  Fbrrrf^  ' 


Tangent  to  Curve? 
Templet  Aids  in  Paper  Locations  of  Turnouts 

were  made.  A  transparent  templet  like  that  shown  can  be  used  to 
advantage.  The  base  line  can  be  set  tangent  to  the  curve  by  the 
offsets,  the  circle  being  placed  at  the  desired  frog  point,  and  the 
line  of  the  frog  can  be  laid  or  pricked  off.  Thus  a  number  of 
trials  can  be  made  without  confusing  the  drawing  by  any  consider- 
able number  of  lines. 


110 


The  Engineer  in  Field  and  Office 


Climate  Should  Govern  Hump  Profiles 

Three  hump  profiles  for  gravity  railroad  yards,  designed  respec- 
tively for  cold,  moderate  and  warm  climates,  were  adopted  on  the 
recommendation  of  the  Committee  on  Yards  and  Terminals  at  the 
recent  convention  of  the  American  Railway  Engineering  Association 
and  will  be  substituted  for  the  profile  now  in  the  "Manual."  As  the 
drawings  indicate,  4%  grades,  reduced  to  1%  over  the  track  scales, 
are  recommended  for  cold  climates  while  for  more  favorable  climates 
the  grades  should  be  lightened  or  shortened,  or  both. 


NQ.J,  FOR  COLD  CLIMATE 


NO.  2,   FOR  MODERATE   CUMATE 


WftJ.    ft?/?  VWffM   CLIMATE 

Colder  Climates  Require  Steeper  Grades 

The  committee  points  out  that  the  problem  cannot  be  solved 
precisely,  since  the  speed  developed  by  cars  depends  not  only  on 
the  type  of  car,  but,  with  the  same  type,  on  the  length,  whether 
loaded  or  empty,  the  lubrication,  efficiency  of  maintenance,  tempera- 
ture, time  standing  before  being  pushed  over  the  hump,  head  winds, 
care  with  which  the  tracks  are  brought  to  and  maintained  at  the 
profile  grade  and,  lastly,  the  timidity  or  assurance  of  the  car  rider. 


Railway  Civil  Engineering 


111 


In  the  estimation  of  the  committee  there  are  these  seven  salient 
features  in  the  design  of  a  hump: 

1.  A  short  grade  steeper  than  the  approach  grade  to  bunch  cars. 

2.  A  level  grade  over  the  summit,  these  grades  to  be  of  such 
length  as  to  form  the  tangent  to  a  reverse  curve  connecting  the 
approach  grade  with  the  first  descending  grade. 

3.  A  short  grade  from  the  summit,  to  separate  the  cars  quickly 
and  give  them  the  desired  speed  for  weighing. 

4.  A  light  grade  over  the  track  scale. 

5.  A  moderately  steep  grade,  the  rate  and  length  depending  on 
the  traffic,  to  the  end  of  the  ladders. 

6.  A  grade  through  the  ladders  sufficient  to  maintain  the  speed 
throughout  the  turnout. 

7.  A  light  grade  that  will  just  overcome  in  the  length  of  the 
body  tracks  the  speed  already  acquired. 

Rails   Located   Before   Concrete   Is   Cast 

The  sketch  shows  a  method  of  setting  U-bolts  to  hold  down  track 
rail  by  which  much  time  was  saved  over  spacing  the  rail  with 
templets  in  constructing  track  for  ore  bridges  at  a  Buffalo  dock. 


Filler 


LEO   WALL 

—Appro*.  10'- — >^ 


of  Dock 


Rail  Holds  Anchor  Bolts  While  Concreting 

Altogether,  2400  ft.  of  125-lb.  rail  was  laid  in  this  way.  It  is  anchored 
by  1-in.  U-bolts  24  in.  apart,  the  ends  of  each  bolt  passing  through 
a  bedplate  on  which  the  rails  rest,  and  the  nuts  on  each  side  holding 


112  The  Engineer  in  Field  and  Office 

down  cast-iron  clips  that  retain  the  rail.  To  space  these  anchor 
bolts,  templets  of  2-in.  pine  were  first  used,  but  the  method  was 
abandoned  after  the  completion  of  the  first  120  ft.,  because  it 
delayed  concreting  and  there  was  difficulty  in  maintaining  the  bed- 
plates at  the  proper  elevation. 

The  method  shown  in  the  sketch,  which  involved  hanging  the  rail 
in  place  before  concreting,  was  substituted.  A  pipe  spreader  is 
used  at  each  anchor,  as  shown  in  the  sketch,  to  hold  the  bolt,  bedplate 
and  clips  in  position.  The  rail  is  leveled  by  the  wing-nuts  at  the  top 
of  the  hanger  rods  and  lined  by  slipping  the  block  under  each  of 
these  nuts  one  way  or  the  other,  before  concreting.  While  the  con- 
crete is  still  green,  the  top  of  the  rail  is  checked  for  grade.  Short 
1  x  4-in.  spreaders  from  the  form  studs  to  the  web  of  the  rail  hold 
the  latter  to  line. 

Making  Borings  for  Embankment  Subsidence 

Borings  were  made  to  test  the  subsidence  of  embankments  in 
connection  with  the  Government  valuation  of  the  Chicago,  St.  Paul, 
Minneapolis  &  Omaha  Ry.  The  tools  used  on  the  work  were  a 
carpenter's  2-in.  auger,  a  2-in.  pod  auger,  a  short  drill,  two  bars,  5 
and  8  ft.  long  respectively,  both  of  1-in.  drill  steel,  a  supply  of  2-in. 
single-strength  pipe  and  couplings  for  casing  the  hole  in  soil  that 


u-"' 
Extension  Bar  for  Boring  Auger 

caved,  a  pipe  lifter  and  pipe  holder,  wooden  mauls  for  driving  the 
casing,  a  shovel  and  post-hole  digger  for  use  in  going  through  the 
ballast,  a  short  piece  of  heavy  log  chain  with  hook  and  eye,  two 
pipe  wrenches  and  a  supply  of  extension  rods.  The  augers  and  drill 
each  had  a  shank  4  ft.  long  with  an  eye  at  the  upper  end  so  that  an 
extension  rod  could  be  hooked  on  as  the  hole  was  lowered.  These 
extension  rods  were  of  i-in.  round  steel,  8  ft.  long,  with  an  eye  at 


Railway  Civil  Engineering  113 

one  end  and  a  hook  at  the  other.  As  some  of  the  holes  were  more 
than  50  ft.  deep,  to  unscrew  joints  every  time  the  auger  was  pulled 
up  for  cleaning  would  have  been  slow  work.  With  the  hook  connec- 
tions the  rods  were  disconnected  as  fast  as  they  were  pulled  up,  and 
there  was  no  chance  for  sections  to  separate  while  in  the  hole.  There 
was  one  rod  4  ft.  long  to  use  in  connection  with  the  longer  ones, 
so  that  there  was  never  more  than  4  ft.  out  of  the  ground  at  a 
time. 

The  method  followed  in  making  these  tests  was  to  put  a  hole 
through  the  ballast  with  the  shovel  and  post-hole  digger,  then  set  in 
a  length  of  the  2-in.  casing  and  use  the  auger  the  rest  of  the  way, 
lowering  the  casing  as  the  hole  progressed.  If  the  fill  was  of  clay  or 
any  material  that  would  stand  without  caving,  it  was  often  possible 
to  complete  the  hole  with  only  the  one  piece  of  pipe,  as  that  would 
keep  the  ballast  out  of  the  hole.  Where  the  fill  was  dry  sand,  or  if 
there  was  water  on  the  sides  of  the  fill,  it  was  necessary  to  keep  the 
casing  close  to  the  bottom  of  the  hole;  and  in  some  holes  better 
progress  was  made  with  the  casing  driven  lower  than  the  hole,  the 
material  being  bored  out  inside  of  the  casing. 

In  a  number  of  holes  small  gravel  stones  were  found  which 
caused  a  great  deal  of  trouble,  until  the  writer  had  a  3-ft.  piece  of 
H-in.  pipe  (the  largest  that  would  go  inside  the  2-in.  casing)  fitted 
with  an  eye  at  one  end  so  that  the  extension  rods  could  be  hooked  in. 
This  pipe  was  churned  up  and  down  in  the  hole  until  the  gravel  had 
become  wedged  in  the  pipe.  In  this  way  any  stone  that  would  go  in 
that  pipe  could  be  removed.  At  times  the  stones  were  too  large  to 
be  removed  in  that  way,  and  it  was  necessary  to  drive  the  casing 
down  until  the  stone  was  wedged  in  it.  The  casing  was  then  pulled 
and  cleaned.  In  some  holes  it  was  possible  to  replace  the  casing 
without  losing  any  of  the  hole,  but  at  other  times  it  was  found  that 
from  5  to  50%  of  the  hole  had  filled  and  would  have  to  be  bored  out 
again. 

How  Softened  Concrete  Lining  To 
Tunnel    Will    Be    Repaired 

Plans  have  been  made  to  repair  the  concrete  lining  to  the  Cascade 
tunnel  of  the  Great  Northern  Ry.,  which  has  softened  due  to  the 
formation  of  sulphur  compounds  from  sulphur  in  the  locomotive 
gases  and  the  cement.  As  the  lining  was  put  in  principally  to 
protect  the  rock  face  against  disintegration  and  not  for  strength, 
and  as  the  steam  locomotives  are  now  superseded  by  electric  trac- 
tion, it  is  thought  that  repairs  made  now  will  be  permanent. 


114 


The  Engineer  in  Field  and  Office 


The  proposed  method  of  repair  is  as  follows:  (1)  Clean  the 
entire  area  of  sidewalls  and  arch,  removing  all  disintegrated  por- 
tions. After  cleaning,  the  surface  of  the  concrete  is  to  be  sprayed 
with  an  alkaline  solution  for  neutralizing  the  acid  in  the  concrete. 

(2)  Drill  2-in.  holes  where  necessary  to  provide  additional  drainage. 

(3)  Drill  4-in.  holes  in  the  arch  where  necessary  and  fill  cavities 
existing  back  of  the  concrete  lining  with  sand  filling  or  grouting. 

(4)  Replace  all  disintegrated  portions  of  the  lining  with  a  coating  of 
concrete  by  a  cement  gun.     The  specifications  provide  that  where 
the  coating  is  over  3  in.  deep  it  shall  be  supported  by  wire  mesh 
cut  to  fit  and  fastened  to  the  old  concrete  by  spikes  driven  into 
holes  drilled  in  the  concrete  24  in.  apart.    The  mixture  for  use  in  the 
cement  gun  will  be  one  part  portland  cement  and  3i  parts  sand, 
mixed  dry. 

Turntable  for  Handling  Relay  Rails 

The  turntable  shown  in  the  accompanying  sketch  is  proving  a  big 
labor  and  time  saver  in  handling  rails  for  the  new  car-repair  yard 
of  the  Pennsylvania  R.R.  now  under  construction  at  Greenville,  New 
Jersey. 

The  85-lb.  rails  used  are  second-hand,  and  the  ball  of  each  is  badly 
worn  on  one  side.  Since  it  is  therefore  necessary  to  place  the  un- 
worn side  on  the  inside  of  the  track  being  laid,  it  happens  that  many 


r 


Device  Saves  Much  Time  in  Handling  Old  Rails 

of  the  rails  have  to  be  turned  end  for  end  before  placing  them. 
Previous  to  building  the  turntable  it  required  considerable  maneuv- 
ering by  a  gang  of  at  least  six  men  to  turn  one  rail.  With  the 
turntable,  however,  which  is  set  up  about  18  ft.  from  the  track 
being  laid,  two  men  can  turn  a  rail  with  ease.  The  device  was  made 
complete  for  $8. 


Railway  Civil  Engineering  115 

Open-Tank  Creosote  Treatment  of  Timber 

Open-tank  treatment  of  timber  is  desirable  for  interurban  and 
the  smaller  steam  railroads  that  have  a  number  of  timber  bridges 
and  other  timber  structures  to  maintain.  Such  a  plant  is  convenient 
for  treating  fence  posts,  paving  blocks  and  the  like  on  very  short 
notice. 

The  Virginia  Railway  and  Power  Co.  has  operated  an  open-tank 
treating  plant  at  Norfolk,  Va.,  since  May  1,  1914,  using  dead  oil 
of  coal  tar  from  its  own  gas-works  as  a  preservative.  Water-gas 
tar  was  tried  as  an  experiment  for  a  few  months  and  finally 
abandoned  because  of  the  small  saving  and  its  doubtful  value. 

Yellow  pine,  mostly  of  merchantable  grade,  has  been  the  only 
species  of  timber  treated  in  the  open  tank,  and  has  varied  in  size 
from  2  x  4-in.  to  14  x  14-in.  timber  of  all  lengths.  A  number 
of  pine  poles  have  also  been  satisfactorily  treated.  The  penetration 
obtained  has  been  from  12  to  20  Ib.  per  cu.ft.  of  timber. 
Well-seasoned  timber  is  desirable  for  open-tank  treatment;  in  the 
case  of  green  timber  it  is  necessary  to  keep  it  in  the  tanks  until 
it  becomes  well  seasoned  from  the  heated  oil. 

The  method  of  treatment  is,  first,  to  place  the  timber  in  the 
tank  and  weight  it  to  prevent  floating,  and  then  cover  it  with 
oil.  The  steam  is  turned  on  for  about  eight  hours,  at  approximately 
100  Ib.  pressure,  the  oil  being  kept  at  about  200°  F.  The  steam  is 
then  cut  off  and  the  oil  and  timber  are  allowed  to  cool  over  night. 
The  next  day  the  timber  is  removed  from  the  tank  and  placed  on 
the  storage  piles  by  the  derrick  boom. 

The  following  figures  give  the  actual  cost  of  treating  at  this 
plant  for  one  month.  One  foreman  (who  also  operates  the  electric 
derrick)  at  $3,  one  fireman  at  $1.50  and  four  laborers  at  $1.50  per 
day  are  required,  working  under  the  bridge  supervisor.  A  total 
of  39,098  ft.  b.m.  was  treated.  The  costs  were  as  follows: 

Cost  per 
Item  Total  M  Ft.  B.M. 

Dead  oil  of  coal  tar.  7375  gal.  at  6Jc $479.38  $12.23 

Coal,  6800  Ib.  at  $3  per  ton 9.10  .23 

Labor,    including    foreman 83.50  2.14 

Maintenance   of   plant 20.00  .51 

Interest  on  $3000   investment 15.00  .38 


Total  expense  for  one  month $605.98  $15.49 

Average  penetration,  19.6  Ib.  per  cu.ft.  of  timber. 

The  drawing  shows  the  layout  of  the   treating  plant.     The 
smaller  tank  is  used  for  treating  only  in  emergencies.     The  dead 


116 


The  Engineer  in  Field  and  Office 


oil  of  coal  tar  is  brought  from  the  gas-works  in  a  2200-gal.  tank-car 
that  is  fitted  with  a  section  of  pipe  to  allow  filling  the  treating 
tanks  directly. 


.--Tomb  Car  in  Position  -for  Filling 


SPUR    TRACK 


1 


\OPEN  TREATING  TANK  10'*4O 

\OHhecrtedbyrSfeam  Coil 
•  covering  Bottom  of  Tern  If 


STORAGE  TANK +-/<?* 34- X2-Z' 

\ 
\ 


t 

—C^\ 

i 

& 

..-ELECTRIC  MOTOR 

vy 

-Hp.Boifa 

TIMBER 
Treating-Tanks  Filled  Directly  from  Car 


1 

I / 


/ 


I''' 

-4-t 


This  company  is  very  well  satisfied  with  the  results  obtained. 
Of  course,  the  company  is  unable  to  determine  the  life  of  this 
newly  treated  timber,  but  is  expecting  a  life  of  at  least  15  years 
for  bridge  timbers,  and  the  same  from  ties  when  protected  from 
mechanical  wear  by  tie-plates. 

Over-breakage  Payment  in  Thorough-Cut 

If,  in  railroad  thorough-cut  construction,  the  solid  rock 
excavation  be  divided  into  two  classes,  (1)  material  within  the 
slopes,  (2)  breakage,  and  if  prices  be  fixed  on  both  classes,  the 
price  on  the  latter  (breakage)  being  sufficient  to  reimburse  the 
contractor  for  handling  this  material  but  not  large  enough  to 
warrant  the  excessive  use  of  explosives,  the  result  should  be 
beneficial  to  both  parties  to  the  contract. 

The  railroad  company  will  pay  no  more  for  the  breakage  than 
it  is  worth  in  the  embankment,  and  the  contractor  can  use  enough 
powder  to  break  the  rock  to  the  slopes,  thus  avoiding  expensive 


Railway  Civil  Engineering  117 

trimming,  without  being  up  against  the  judgment  of  the  engineer 
as  to  whether  or  not  he  will  be  paid  for  the  material  outside  of 
the  slopes. 

This  "in  the  judgment  of  the  engineer"  clause  about  the  use  of 
powder  and  breakage  often  leads  to  two  bad  results:  First,  loose 
stones  are  left  hanging  to  the  side  of  the  cut,  which  should  be 
taken  down  under  construction,  but  are  not  and  consequently  have 
to  be  removed  under  operation.  They  frequently  fall  on  the 
roadway  and  sometimes  cause  a  serious  wreck.  Second,  expensive 
controversies  which  may  lead  to  more  expensive  lawsuits  are  the 
logical  outcome  of  this  "in  the  judgment  of  the  engineer"  clause. 

Safe  Stresses  Shown  by  Broken  Timber 

The  occasional  failure  of  the  stringers  of  pile  bridges  has  been 
found  to  be  pretty  definitely  related  to  the  weight  of  locomotives 
operating  over  them.  On  the  Atchison,  Topeka  &  Santa  Fe  Ry. 
two  kinds  of  stringer  arrangements  exist  on  the  line,  heavy  and 
light,  and  the  more  frequent  failure  of  stringers  in  the  light  floor 
construction  drew  attention  to  this  relation. 

All  spans  are  14  ft.,  and  the  stringers  are  made  of  Southern 
(Texas  or  Louisiana)  yellow  pine  7  x  16  in.  in  section,  except  that 
Oregon  fir  is  used  on  lines  west  of  La  Junta.  In  the  heavy  floors 
used  on  main  line  and  important  branches  there  are  four  pieces 
per  rail,  set  side  by  side  with  1-in.  clear  space  provided  by 
separator  washers  on  the  through-bolts.  The  light  floor  used  on 
some  branch  lines  has  three-ply  stringers.  During  the  past  years 
a  number  of  breakages  of  sticks  in  the  three-ply  stringers  has 
occurred.  Only  one  stick  breaks  at  a  time;  and  thus  the  breakages 
do  not  mean  accidents,  although  they  call  for  immediate  repair 
work. 

It  was  concluded  that  reinforcement  to  four-ply  construction  is 
now  needed  on  many  of  the  branch  lines.  Studies  of  bending 
moments  in  stringers  were  made  to  give  more  certain  foundation 
to  this  conclusion.  Some  of  the  failures  are  of  the  longitudinal  shear 
or  splitting  type,  and  others  are  bending-stress  failures.  The 
stress  investigations,  however,  were  made  with  reference  to  bending 
moment  alone. 

The  first  general  fact  was  that  locomotives  whose  total  driver 
weights  exceed  100,000  Ib.  for  Atlantic,  140,000  Ib.  for  Pacific  and 
157,000  Ib.  for  Consolidation  engines  are  likely  to  produce  breakages 
in  three-ply  stringers.  On  the  other  hand,  four-ply  stringers  gave 
no  trouble  anywhere  on  the  system. 


118 


The  Engineer  in  Field  and  Office 


The  railway  company's  standard  bridge  loading  produces  on 
14-ft.  span  a  bending  moment  equivalent  to  E-47  loading.  It 
produces  an  extreme-fiber  stress  of  1400  Ib.  per  sq.in.  in  four-ply 
and  1860  Ib.  per  sq.in.  in  three-ply  stringers.  Various  actual 
engines  used  on  the  line  gave  the  following  bending  stresses  in 
three-ply  construction:  1520,  1780,  1824,  1792  and  1740  Ib.  per 
sq.in.  These  figures  contain  no  allowance  for  impact. 

The  engines  studied  include  some  four-cylinder  balanced 
compounds  which  produce  a  low  impact  effect,  while  others  produce 
a  high  counterbalance-weight  impact.  Partly  for  this  reason  it  was 
not  possible  to  make  a  direct  deduction  from  the  facts.  The  final 
conclusion,  however,  was  that  bending  stresses  below  1500  Ib.  per 
sq.in.  are  safe,  while  loads  whose  static  effect  materially  exceeds 
1500  Ib.  fiber  stress  may  produce  breakages. 

Special  Tongs  Prevent  Rails  from  Seesawing 
While    Being   Handled 

The  sketch  shows  some  simple  rail  tongs  which  have  been 
developed  on  the  Atchison,  Topeka  &  Santa  Fe  Ry.,  and  which 
have  given  good  service.  The  length  of  these  tongs,  2  ft.  8  in. 


Tongs  Hold  Rails  Steady  in  Handling 

between  grips,  is  found  sufficient  to  prevent  rails  from  seesawing 
while  being  handled  by  a  crane.  The  main  part  of  the  tongs 
is  made  from  f  x  3-in.  soft  steel,  the  jaws  being  hinged  on  a 


Railway  Civil  Engineering 


119 


|-in.  bolt  with  a  1-in.  pipe  spreader.  Each  half  of  the  tongs  is 
connected  by  a  2-ft.  length  of  §-in.  chain  to  a  large  ring,  which  is 
hooked  to  the  hoisting  line. 

Concrete  Ties  in  Holland 

An  experimental  track  in  which  the  ties  are  composed  of  pairs 
of  concrete  blocks  connected  by  transverse  steel  tie-bars  is  in 
service  on  the  Amsterdam-Utrecht  line  of  the  Netherlands  State 
Railways,  in  Holland.  In  principle  the  tie  resembles  the  ties  tried 
in  this  country  on  the  Chicago  &  Alton  Ry.,  and  the  cast-iron 
plate  ties  that  have  been  used  extensively  in  India. 

Each  tie  is  composed  of  a  pair  of  reinforced-concrete  blocks 
about  4i  x  3  ft.  on  the  base,  with  a  maximum  height  of  about  12 
in.  The  top  surface  is  about  36  x  18  in.  with  flaring  ribs  to  the 


Sect-ional    Side    Elevo-Hon 


Sectional  Erki  EtevctKon 


Track  with  Concrete  Blocks  and  Transverse  Steel  Channels; 
Netherlands  State  Railways 

corners  of  the  base,  and  its  top  forms  a  seat  for  a  pair  of 
wedge-shaped  wood  blocks.  Upon  the  wood  cushions  of  a  pair  of 
concrete  blocks  rests  the  ends  of  a  transverse  inverted  steel  channel. 
Upon  this  rest  the  92-lb.  T-rails  and  rail  clamps. 

At  each  block  the  rail  is  held  by  a  pair  of  deep  V-bolts,  or 
stirrups,  the  loops  of  which  pass  through  the  projecting  ends 
of  cast-iron  anchors  embedded  in  the  concrete.  The  threaded  ends 
of  the  bolts  pass  through  the  rail  clamps.  In  surfacing  track  the 
adjustments  are  made  by  loosening  these  bolts  and  adjusting  the 
wood  wedges,  the  concrete  blocks  being  left  undisturbed,  as  tamping 
is  liable  to  result  in  causing  cracks. 

The  weight  is  about  440  Ib.  for  each  block.  The  weight  per 
lineal  foot  of  track  is  about  1,500  Ib.,  including  ballast  filled  over 
the  base  of  the  blocks,  but  this  weight  for  the  experimental  track  is 
obtained  at  the  expense  of  the  support  of  the  rail,  the  spacing 
being  4  ft.  c.  to  c.,  or  2  ft.  at  the  rail  joints.  Such  wide  spacing 
of  rail  supports  is  undesirable  in  track  construction,  and  is  only 
introduced  to  minimize  the  cost.  The  experimental  track  is  only 


120  The  Engineer  in  Field  and  Office 

120  ft.  long.  It  carries  considerable  traffic,  but  the  trains  run 
at  low  speed,  as  it  is  near  the  city  of  Utrecht.  It  has  been  in 
service  for  about  two  years  and  is  said  to  be  generally  in  good 
condition,  although  cracks  have  developed  in  some  of  the  blocks. 

Oiling  Flange   Saves   Rail  Wear 

On  the  New  York,  Susquehanna  &  Western  Division  of  the  Erie 
R.R.  the  rail  wear  on  curves  has  been  reduced  two-thirds  by  the 
use  of  flange  oilers  on  the  locomotives,  and  tends  to  prevent  derail- 
ments. 

For  success  in  the  use  of  the  flange  oiler  a  very  heavy  asphaltum 
oil  must  be  used.  The  oil  should  contain  40  to  60%  of  asphaltum 
in  solution  and  be  low  in  grease  and  paraffin.  This  heavy  oil  acts 
as  a  lubricant  between  the  wheel  flange  and  the  head  of  the  rail 
when  a  lighter  oil  would  be  forced  out.  Further  than  this,  the 
heavy  asphaltum  oil  sticks  to  the  flange  and  will  not  work  over  onto 
the  tread  of  the  driving  wheel,  as  will  an  oil  with  a  paraffin  base. 
Many  of  the  troubles  that  have  been  experienced  with  flange  oilers 
are  due  to  the  use  of  oil  that  runs  over  onto  the  tread  and  causes 
the  driving  wheel  to  slip. 

From  an  operating  point  of  view,  the  saving  in  tire  turning  is 
even  more  important  than  the  saving  in  rail  wear.  It  has  been 
estimated  that  the  cost  of  tire  metal  used  up,  labor  and  loss  of 
engine  service  every  time  a  six-driver  locomotive  has  to  go  to  the 
shop  for  turning  tires  on  account  of  sharp  flanges  represents  an 
outlay  of  $219.  Where  freight  locomotives  not  equipped  with  flange 
oilers  will  run  9000  to  12,000  mi.  before  requiring  shopping  to  have 
their  tires  turned,  they  will  run  between  25,000  and  42,000  before 
shopping  if  equipped  with  flange  oilers.  In  passenger  service,  loco- 
motives that  have  to  be  shopped  every  15,000  to  25,000  mi.  should 
run  60,000  to  80,000  mi.  if  equipped  with  flange  oilers. 

Notwithstanding  these  practical  advantages,  the  flange  oiler 
appears  to  have  as  yet  comparatively  limited  use.  The  reason  ap- 
parently is  inertia  on  the  part  of  the  operating  force  and  dislike 
to  equip  locomotives  with  any  appliances  not  absolutely  necessary. 

Raise  Sunken  Bridge  Span  with  Jacks 

A  ninety-foot  pony  truss  span  belonging  to  the  Evansville  & 
Indianapolis  R.R.,  which  was  washed  out  on  the  White  River  near 
Rogers,  Ind.,  was  raised  clear  of  the  water  without  difficulty  by  the 
method  shown  in  the  photographs.  The  span  had  been  carried 


Railway  Civil  Engineering 


121 


about  1000  ft.  downstream,  and  had  landed  in  an  upright  position 
some  50  ft.  from  the  south  bank  of  the  river.  At  low  water  the 
top  3  ft.  of  the  trusses  was  exposed.  The  span  lay  in  a  nearly 
horizontal  position. 

Two  gallows  frames  were  erected,  one  over  each  hip  of  the  span. 
The  legs  of  these  frames  consisted  of  four  pile  towers,  and  the 
cross  beams  of  six  8  x  16-in.  stringers.  Each  hip  joint  was  hung 
from  a  pair  of  H  threaded  rods  18  ft.  in  length.  Above  the  cross 


Nuts  Were  Used  To  Adjust  Jacking  Yoke 

beams  each  pair  of  these  rods  was  connected  by  a  timber  yoke 
bearing  under  nuts  screwed  down  on  the  rods.  The  raising  was 
done  with  two  25-ton  jacks,  the  nuts  being  used  merely  to  adjust 
successive  grips  on  the  rods.  The  ends  of  the  span  were  raised 
alternately,  one  jack  being  set  over  each  joint,  and  each  end  being 
raised  about  2  ft.  at  a  time.  After  the  bottom  flanges  of  the 
floorbeams  cleared  the  water  by  about  4  in.  raising  was  stopped, 
two  additional  bents  of  falsework  placed,  and  the  span  dismembered, 
the  pieces  being  loaded  on  scows  and  taken  to  a  repair  shop  on 
the  north  bank  of  the  river. 


The  Engineer  in  Field  and  Offiu 


Railway  Civil  Engineering  123 

Relining  a  Tunnel  Between  Trains 

A  special  concrete  car  with  a  high  platform  and  a  short  tower, 
a  jacking  car  for  moving  ahead  the  heavy  forms,  and  work  cars  for 
removing  the  old  timber  lining  and  stone  packing  behind  it,  are 
being  used  in  relining  with  concrete  a  single-track  tunnel  5023  ft. 
long  on  the  Union  Pacific  System  at  Aspen,  Wyo.,  where  about  20 
train  movements  take  place  in  the  10-hour  day. 

The  tunnel  being  through  material  that  exerts  considerable  pres- 
sure on  the  lining,  the  forms,  made  of  12-in.  I-beams  shaped  to  the 
tunnel  section  and  spaced  24  in.  apart,  are  set  up  first,  and  the 
roof  load  is  transferred  to  them  before  the  old  timber  is  removed. 
There  is  a  joint  in  each  rib  at  each  side  on  the  springing  line  be- 
tween the  arch  and  post  sections.  To  move  the  ribs  forward,  a 
jacking  car  is  spotted  at  the  right  point  under  the  roof,  and  the 
arch  rib  is  raised  from  the  legs  slightly  by  taking  a  strain  on  a 
double-acting  ratchet  jack  on  the  car.  The  legs  are  released  and 
moved  to  the  next  location,  the  arch  section  is  lowered  till  it  clears 
the  sides  and  top  of  the  other  ribs,  and  the  car  pinched  ahead  till 
the  arch  ring  can  be  adjusted  and  bolted  to  the  legs  in  their  new 
location. 

A  special  platform  car  is  used  in  erecting  these  ribs,  placing  the 
reinforcing  and  removing  the  timber  and  old  packing  behind  it. 
The  platform  is  extended  by  hinged  wings  attached  to  the  sides  of 
the  car,  thus  providing  working  space  for  the  entire  width  of  the 
tunnel.  The  wings  are  folded  down  when  moving  the  equipment. 

Another  special  car  is  in  use  placing  concrete.  On  it  are 
mounted  a  |-cu.yd.  mixer  and  a  concrete  hoist  with  a  bucket  holding 
one  batch.  The  hoist  elevates  concrete  to  a  platform  6  ft.  below 
the  crown  of  the  arch.  From  this  position  it  is  spouted  to  place 
until  the  level  of  the  platform  is  reached,  after  which  shoveling  is 
necessary.  This  car  also  carries  water  tanks  and  the  cement.  Ag- 
gregates are  supplied  in  gondola  cars  and  are  handled  by  wheel- 
barrow. 

By  working  three  openings  200  ft.  apart  it  is  possible  to  keep 
one  gang  of  men  continually  employed  in  form-rib  erection,  timber 
removal  and  excavation,  while  another  gang  is  busy  at  concreting. 
At  the  same  time  the  carpenters  are  building  forms  in  the  third 
opening.  In  this  way  each  unit  of  the  equipment  works  independ- 
ently, the  sequence  of  operation  in  each  cycle  is  maintained  at 
each  point,  and  the  work  is  all  carried  forward  in  one  direction. 


The  Engineer  in  Field  and  Office 


Wood  Block  Guards  Third-Rail  End 

Trouble  is  sometimes  caused  by  faulty  third-rail  shoes  getting 

below  end  approaches  and  thus  breaking  the  insulators  and  tearing 

up  the  rail.    The  accompanying  sketch  shows  how  this  is  prevented 

on  one  railway  property  by  a  wooden  block  placed  in  front  of  a 


Guard  To  Prevent  Third-Rail  Shoes  from  Getting  Under  the  Rail 

third-rail  approach  and  securely  nailed  to  the  ties.  Sufficient  clear, 
ance  is  left  between  the  ends  of  the  block  and  the  rail  to  allow 
for  the  expansion  of  the  latter.  It  has  been  found  that  no  real 
harm  results  if  the  block  accidentally  comes  in  contact  with  the 
rail  since  the  leakage  is  small  even  in  wet  weather. 

Photographic  Survey  of  Proposed  Route 
A  panoramic  photographic  survey  of  the  route  of  the  proposed 
Oregon,  California  &  Eastern  Ry.  has  been  made  in  order  to  show 
the  character  and  possibilities  of  the  country  to  persons  interested. 
The  outfit  used  was  a  camera  capable  of  making  a  picture  8 
in.  wide  and  up  to  4  ft.  in  length.  The  camera  revolves  on  the 
head  of  the  tripod  and  is  driven  by  clockwork  so  as  to  cover  any 
desired  degree  of  a  circle.  From  a  high  point  it  was  possible  to 
cover  a  distance  of  10  to  30  miles.  In  most  cases  it  was  found 
practicable  to  set  up  on  a  mountain  or  butte  in  such  a  position 
as  to  take  a  view  from  one  valley  to  another,  the  points  being 
selected  by  the  engineer.  Each  picture  was  begun  at  about  the 
point  where  the  previous  one  ended. 

It  required  31  pictures,  each  3  to  4  ft.  long,  to  cover  the  entire 
route.  This  work  consumed  19  days,  as  much  time  was  taken  in 
getting  to  and  from  the  view-points.  Pictures  were  taken  only 
under  favorable  conditions  of  light,  atmosphere  and  absence  of 
wind,  in  order  to  get  good  results.  After  the  photographs  had 
been  made,  the  chief  engineer  had  a  draftsman  plot  the  line  of 
the  survey  upon  each  picture,  so  as  to  show  the  cuts,  fills,  structures 
and  other  main  features. 


Concrete  Construction 


125 


Metal    Stencil   Signs    Need   No   Painting 

Sheet-iron  signs  with  the  inscriptions  punched  out  are  being  in- 
troduced by  the  Canadian  Pacific  Ry.  to  eliminate  the  cost  of  peri- 
odical painting  and  lettering.  Such  signs  require  nothing  but  a 
coat  of  paint  at  long  intervals,  and  no  painting  of  letters  or  numbers. 


Punched  ou+ Disks 


SLOW  Of 

4-,%'R'ivefs 

Punched  out 
Letters 


^Order 
Bridge  Number  Sign 

Track  Signs  with  Figures  Perforated  Are  Used  by 
Canadian  Pacific  Railway 

The  bridge-number  sign,  a  TVin.  plate,  attached  to  the  end  of 
a  tie  by  lagscrews,  costs  from  75c.  to  $1.  Mile-number  signs  are 
similar  plates  secured  to  telegraph  poles.  Such  signs  should  last 
about  50  years.  A  wood  sign  costing  $1.25  will  last  12  years  and  has 
to  be  painted  and  lettered  every  three  years  at  a  cost  of  75c. ;  for 
a  48-year  period  its  total  cost  becomes  $17. 

Snowplow  and  whistle  signs  are  fixed  on  boiler-tube  posts.  Two 
6-in.  holes  are  punched  in  the  target  for  the  former  sign  and  a 
"W"  for  the  latter.  Metal  "stop"  and  "slow"  signs  cost  $2.75  each. 

Helpful  Suggestions  from  Recent  Concrete 
Construction 

Caustic  Soda  and  Cement  Stop  Leaks 

When  leaks  develop  in  concrete  work  it  is  generally  too  late  in 
any  case  to  remedy  the  cause,  and  the  only  thing  left  to  do  is  to 
stop  them,  sometimes  at  the  expense  of  considerable  money  to  the 
contractor  and  worry  to  the  engineer. 


126  The  Engineer  in  Field  and  Office 

This  is  often  done  by  piping  the  flow  to  one  point,  grouting  in 
the  pipe  while  it  is  passing  the  water,  cutting  the  pipe  off  within 
the  surface  of  the  concrete  and  capping  it,  after  which  the  hole 
left  over  the  pipe  is  plastered  up.  This  is  a  slow,  expensive  and 
puttering  way  of  doing  the  job.  Frequently  the  pipe  rusts,  dis- 
coloring the  concrete  and  sometimes  reopening  the  leak.  There  is 
always  danger  of  this  if  the  pipe  is  exposed  to  electrolytic  action. 
Leaks  may  also  be  calked  before  plastering  with  jute,  or  with  lead 
wool  and  wood  wedges.  Jute  will  only  do  for  small  leaks  without 
much  pressure,  and  many  engineers  do  not  approve  of  the  use  of 
wood  left  permanently  in  the  concrete. 

To  overcome  these  objections,  the  method  referred  to  was  de- 
veloped on  the  Catskill  Aqueduct  and  Passaic  Valley  sewer,  where 
leaks  which  occurred  months  after  the  completion  of  portions  of 
the  work  caused  considerable  trouble.  The  section  of  concrete 
around  the  leak  is  cut  out  to  a  depth  of  3  or  4  in.  with  a  chisel 
so  that  the  hole  is  larger  at  the  base  than  at  the  surface.  A  small 
quantity  of  fresh  portland  cement  is  then  mixed  with  a  boiling- 
hot  solution  of  caustic  soda  into  a  thick  paste,  which  is  applied 
rapidly  with  the  hands  (which  should  be  covered  with  rubber 
gloves)  to  one  side  of  the  cavity.  The  plaster  is  pressed  firmly 
against  the  old  concrete  and  held  for  a  minute  or  more.  In  this 
length  of  time  it  sets  very  hard  and  can  only  be  removed  with  a 
chisel.  This  operation  is  repeated,  following  around  the  sides  of 
the  cavity,  until  a  small  opening  remains,  through  which  the  water 
is  now  flowing.  This  small  opening  is  again  shaped  with  a  chisel 
till  the  bottom  is  larger  than  the  opening  at  the  surface.  Enough 
freshly  mixed  paste  is  then  taken  in  the  hand  completely  to  fill  this 
opening,  and  applied  suddenly  with  one  hand,  holding  the  paste  in 
place  for  a  few  minutes.  If  the  work  has  been  done  well,  the  leak 
will  be  completely  closed. 

Practice  is  required  for  the  successful  use  of  this  method,  and 
there  are  several  important  points  to  be  carefully  observed.  The 
soda  must  be  of  the  best  quality  and  fresh,  very  concentrated  and 
mixed  with  very  little  water.  The  mixture  must  be  boiling  hot 
when  the  cement  is  added,  and  the  latter  must  also  be  perfectly 
fresh.  Very  little  of  the  paste  should  be  prepared  at  one  time,  as 
it  hardens  almost  instantly.  Just  enough  of  the  soda  solution  should 
be  used  to  make  a  stiff  paste,  which  should  be  mixed  very  rapidly 
by  kneading  it  with  the  hands. 


Concrete  Construction  127 

One  Year's  Tests  of  Field-Made  Concrete 

Compression  tests  of  8  x  16-in.  cylinders  cast  from  concrete 
taken  from  forms  have  been  made  on  practically  all  the  work  under 
the  jurisdiction  of  the  New  York  Public  Service  Commission,  in 
connection  with  the  construction  of  the  new  rapid-transit  lines 
in  New  York  City.  The  results  of  one  year's  series  of  such  tests 
have  been  collected  in  the  accompanying  table,  to  which  have  been 
added  for  purposes  of  comparison  the  compression  values  prescribed 
by  the  final  report  of  the  Joint  Committee. 

RESULTS  OF  ONE  YEAR'S  TESTS  ON  FIELD-MADE  1:2:4  CONCRETE 
BY  NEW  YORK  PUBLIC   SERVICE  COMMISSION* 

No.  of  No.  of    Increased 

28  Days,     Tests     90   Days,     Tests     Over  Cor- 

Average     Repre-    Average     Repre-  responding 

Lb.  per    sented  in  Lb.  per    sented  in     2  8 -Day 

Sq.In.     Average     Sq.In.     Average       Tests 

Average  of  all  tests 1725  84  2100  59  21% 

Coarse  Aggregate: 

Mixed    Long    Island    beach    sand 

and    gravel     2155  11  2370  8  24% 

Lond  Island  beach  gravel 1880  10  2185  3  18% 

Hudson  River  limestone 1880  10  2240  10  14% 

Hudson   River   dolomite 1790  4  2280  3  23% 

Hudson   River   traprock 1630  16  2035  10  17.5% 

Long  Island  bank  gravel  (washed)   1550  31  1990  24  25% 

Fine  Aggregates : 

Sand  excavated  on  the   work...      1775  9  2285  7  25% 

Long  Island  beach  sand 1690  24  2020  13  15.5% 

Long  Island  bank  sand    (washed)  1610  38  2050  30  21% 

Hudson   River   bank   sand 1135  1  1837  1  62% 

Consistency : 

Medium    2220  18  2425  14  10% 

Wet   (stiff  enough  to  keep  coarse 
aggregate      from      settling      to 

bottom)      1710  47  2070  39  24.5% 

Very  wet    (coarse  aggregate  set- 
tles   to    bottom) 1580  13  2300  1  33% 

Extra  wet    (soupy) 1185  7  1320  6  10% 

Mixer : 

Machine     1750  80  2100  59  21  % 

Hand     1290  4             ..  .... 

Joint  Committee : 

Granite  and  traprock 2200  .  .  ....  .  .  .... 

Gravel,      hard      limestone,      hard 

sandstone     2000  ..  ....  ..  .... 

Soft  limestone  and  sandstone. ...    1500  . .  ....  . .  .... 

*A11  tests  of  doubtful  accuracy  have  been  omitted,  and  in  computing  the 
averages  the  result  of  any  test  that  differed  more  than  50%  from  the  average 
has  been  excluded.  Each  test  consists  of  three  specimens.  Aggregates  wore 
specification  material  in  every  case.  Dimensions  of  specimen  cylinders,  8  in.  in 
diameter  by  16  in.  high. 

How  Much  Water  for  Road  Concrete? 

The  proper  amount  of  water  to  use  in  concrete  to  be  placed 
in  concrete  roads  is  slightly  more  than  the  amount  that  will  give 
a  maximum  strength.  This  is  because  the  maximum-strength 
content  gives  a  consistency  that  is  too  difficult  to  work,  and  a 
balance  between  strength  and  operating  facility  has  to  be  made. 


128 


The  Engineer  in  Field  and  Office 


Tests  were  made  at  the  Lewis  Institute  on  a  number  of  6  x  12-in. 
compression  cylinders,  made  in  mixes  ranging  from  one  part  cement 
and  nine  parts  aggregate  to  one  part  cement  and  two  parts 
aggregate.  The  aggregate  consisted  of  a  mixture  of  sand  and 
pebbles  graded  in  size  from  the  finest  particles  up  to  li  in.,  and 
the  same  grading  was  used  throughout. 

The  tests  show  that  the  effect  of  proportional  changes  in  the 
mixing  water  is  approximately  the  same  for  all  mixes  of  concrete. 
Therefore  a  composite  curve  was  drawn  to  show  the  average  effect. 


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Per  Cent,  of  Water  giving  Maximum  Strength 

How  Excess  Water  Affects  Concrete  Strength 

This  curve  is  reproduced  herewith.  In  it  the  ordinates  represent 
the  relative  strength  of  concrete  expressed  as  a  per  cent,  of  the 
maximum  that  can  be  secured  from  a  given  amount  of  cement 
and  the  same  aggregate.  The  abscissas  indicate  the  relative 
quantity  of  water  used  in  the  mix,  considering  the  amount  that  gives 
the  maximum  strength  as  100%.  It  will  be  noticed  that  there  are 
no  definite  figures  given,  because  the  proper  amount  of  water 
varies  with  the  method  of  handling  and  placing  the  concrete,  the 
condition  of  the  aggregate,  the  temperature  of  the  outside  air 
and  a  number  of  other  factors. 

As  a  rule,  the  amount  of  water  that  gives  the  maximum  strength 
produces  a  mix  that  is  too  stiff  for  most  purposes,  though  in 
cast-concrete  products  a  mix  even  drier  than  that  which  gives  the 
maximum  strength  is  sometimes  desirable,  because  the  molds  can 


Concrete  Construction  129 

thus  be  removed  within  a  short  time.  The  general  conditions, 
however,  are  shown  in  the  curve.  It  will  be  observed  that  concrete 
strength  increases  rapidly  with  the  quantity  of  water  up  to  the 
optimum  condition.  With  any  further  increase  in  the  amount  of 
water  there  is  a  rapid  falling  off  of  the  strength,  so  that  with  an 
amount  of  water  about  double  that  required  for  the  higher  strength 
the  concrete  has  only  about  20%  of  the  maximum  strength. 

In  building  concrete  roads  the  consistency  which  is  recommended 
corresponds  to  about  105  to  115%  of  that  giving  the  strongest  con- 
crete. The  economies  resulting  from  handling  the  concrete  are  more 
important  than  securing  the  maximum  possible  strength  for  a  given 
amount  of  cement.  It  has  been  observed  that  many  road  contractors 
insist  on  using  water  varying  between  130  and  200%  of  that  corre- 
sponding to  the  highest  strength,  with  the  effect  on  the  strength 
noted  in  the  curve.  Had  this  curve  extended  beyond  the  200%  water, 
it  would  have  been  practically  flat,  thus  indicating  that  the  maximum 
of  damage  is  caused  at  that  point. 

The  proper  quantity  of  water  will  vary  with  the  quantity  of 
cement  and  the  size  and  grading  of  the  aggregate,  and  to  a  less 
degree  with  the  nature  of  the  aggregate.  The  water  required  for 
a  sand  and  crushed-stone  aggregate  is  not  appreciably  different 
from  that  required  of  a  sand  and  pebble  mixture,  provided  the 
grading  of  the  aggregates  is  similar.  But  there  is  no  direct 
criterion  for  determining  in  advance  the  best  quantity  of  water  for 

WATER  REQUIRED  FOR  ROAD  CONCRETE 

, Mix N  Approximate  Mix  as  Usually               Water  Required 

Volume    of  Expressed  (Gallons    per    Sack    of 

Aggregate  /—^-Aggregate N  Cement) 

Cement    After  Mixing  Cement            Fine           Coarse  Minimum         Maximum 

1                     5  1                     2                     4                        6                        6J 

1                     4i  1                     2                      3                       5f                     6| 

14  1                      li                    3                        5|                      6 

13  1                      11                    2i                      5                         5i 

concrete  being  placed  on  a  road.  The  concrete  should  be  mixed 
so  that  only  a  small  quantity  of  free  water  will  appear  on  the 
surface  after  leveling  and  striking  off,  which  gives  concrete  of  a 
jelly-like  consistency. 

The  principal  difficulty  in  the  way  of  attempting  to  determine 
in  advance  the  proper  quantity  of  water  is  due  to  the  fact  that 
aggregates  are  generally  damp,  and  the  degree  of  dampness  is  not 
uniform.  In  the  case  of  concrete  made  of  sand  and  pebbles,  or 
sand  and  crushed  stone,  well  graded  in  sizes  up  to  1£  in.,  the 
accompanying  table  indicates  about  the  quantity  of  water  that 
should  be  used  for  the  mixes  commonly  employed  in  concrete  roads. 
It  is  assumed  that  the  aggregates  are  in  a  room-dry  condition, 
which  does  not  always  prevail  in  work. 


130  The  Engineer  in  Field  and  Office 

Effect  of  Hydrated  Lime  on  Concrete 

The  Bureau  of  Standards  some  time  ago  started  an  exhaustive 
series  of  tests  looking  into  the  effect  of  hydrated  lime  on  concrete, 
as  regards  strength,  consistency,  watertightness  and  workability. 
A  preliminary  announcement  gives  some  conclusions,  based  on  six 
months'  tests,  as  to  the  effect  on  strength.  The  results  should  be 
used  with  caution  and  hold  only  for  hand-mixed,  tamped  concrete, 
of  rather  dry  consistency  and  stored  in  a  damp  closet.  There  is 
no  evidence  at  present  to  show  the  effect  of  the  hydrate  on  concrete 
which  is  either  machine  mixed,  poured  or  aged  in  air,  and 
interpretation  of  the  present  conclusion  to  obtain  such  information 
is  not  justifiable. 

The  following  conclusions  have  been  reached:  (1)  The 
substitution  of  hydrated  lime  for  cement  causes,  in  general,  a 
diminution  of  the  compressive  strength  of  the  concrete.  This  is 
most  pronounced  with  1:2:4  concrete.  (2)  Hydrated  lime  causes 
a  less  diminution  of  strength  in  a  1 :  14 :  3  concrete  than  in  a  1 :  2 :  4. 
Results  indicate  that  the  sizing  of  the  ingredients  may  be  one  of 
the  important  factors  in  determining  the  value  of  hydrated  lime 
in  concrete.  (3)  At  least  up  to  six  months,  there  is  no  appreciable 
difference  in  behavior  between  high  calcium  and  high  magnesian 
hydrate.  (4)  The  diminution  of  strength  caused  by  hydrate  when 
1:  14:  3  concrete  is  stored  in  air  is  not  nearly  so  great  as  when 
the  concrete  is  stored  in  the  damp  closet. 

Link  Expansion  Joints  on  Viaduct 

Measurements  taken  between  extremes  of  temperature  for  a 
year  on  the  linked  expansion  joints  of  the  Colfax-Larimer  viaduct 
in  Denver  indicate  that  all  joints  work  as  nearly  equally  as  could 
be  hoped  for.  The  structure  consists  of  alternate  towers  and 
suspended  spans,  the  latter  having  lengths  one-half  the  distance 
between  bents  and  being  supported  by  links  upon  the  overhanging 
girders  of  the  towers.  With  favorable  results  on  the  structure 
proper,  on  which  to  base  the  design  of  the  joints  in  the  pavement, 
the  problem  was  to  make  provision  for  movement  approximately 
every  80  ft.,  in  such  a  way  that  there  would  be  as  little  annoyance 
as  possible  to  traffic.  Plates  or  angles  projecting  in  roadways 
are  somewhat  of  a  nuisance,  and  the  thickness  of  the  asphaltic 
pavement  did  not  render  a  built-up  joint  feasible. 

The- joints  adopted  have  undergone  the  test  of  an  exceptionally 
severe  winter  in  Denver,  some  being  pulled  apart  at  least  I  in. 


Concrete  Construction  131 

without  as  yet  showing  any  need  of  repair;  and  as  for  ease  of 
riding,  a  crack  in  an  asphaltic  pavement  gives  less  shock  to  a 
vehicle  than  almost  any  other  form  of  joint. 

One  other  point  in  the  design  of  the  viaduct  having  to  do  with 
expansion,  which  has  caused  some  anxiety,  is  the  laying  of  sidewalk 
slabs  of  4-in.  thickness  directly  upon  the  old  concrete  of  the  super- 
structure itself.  Although  these  slabs  are  completely  severed  by 
transverse  joints  at  intervals  of  about  5  ft.,  they  are  monolithic  with 
the  curb ;  and  there  was  some  fear  that,  being  exposed  to  the  atmos- 
phere, their  rates  of  contraction  would  be  different  from  that  of  the 

M 18,  Gal  Steel 
21"  Wide  before 
Elastic  Joint 


Sidewalk  Exp.  Joint  Exp  joint   in 

Expansion  Joints  Are  Different  at  Track,  Roadway  and  Sidewalk 

concrete  underneath,  which  difference  might  result  in  surface 
cracking  and  possible  shattering  after  long  exposure.  There  was 
some  thought  of  painting  the  joint  with  tar  pitch  or  asphalt  paint; 
but  it  was  finally  concluded  that  this  would  be  ineffective,  since  the 
concrete  of  the  underlying  superstructure,  being  more  or  less  lumpy, 
the  painting  would  not  overcome  the  resistance  of  the  mechanical 
bond.  This  possible  trouble  could  have  been  avoided  by  making 
the  sidewalk  monolithic  with  the  superstructure,  but  previous 
experience  along  this -line  showed  that  it  would  be  impossible  to 
obtain  either  a  surface  to  grade  or  a  good  alignment  of  the  curbing. 

Double  Shell  Concrete  Chimney 

A  special  arrangement  of  the  interior  shell  and  the  use  of 
adjustable  steel  forms  to  give  an  exterior  taper  are  the  features  of 
the  reinforced-concrete  chimney  at  the  plant  of  the  Rockford  Paper 
Box  Board  Co.,  Rockford,  Illinois.  It  is  187  ft.  high  with  an 
interior  diameter  of  7  ft.  throughout.  The  outside  diameter  is  10 
ft.  4  in.  at  the  footing  and  9  ft.  at  the  top,  with  a  taper  of 
0.056  in.  per  foot,  commencing  at  the  top  of  the  breeching.  The 
inner  shell  has  been  carried  nearly  to  the  top  in  order  to  protect 
the  outer  wall  and  to  improve  the  draft  efficiency 


132 


The  Engineer  in  Field  and  Office 


If  the  gases  are  only  slightly  cooled  and  come  in  contact  with 
a  relatively  thick  portion  of  the  outer  wall,  they  heat  its  inner 
surface  while  the  exterior  may  be  exposed  to  very  cold  weather. 
As  concrete  is  a  poor  conductor  of  heat,  this  condition  results  in 
severe  internal  stresses,  and  observations  of  many  chimneys  built 
in  this  way  indicate  that  the  most  serious  cracks  occur  about 
the  level  of  the  top  of  the  short  interior  wall. 


I   :   :  i   ! 

Elevation  at  Breeching 


f....  7>  ....>,- 
Plan  at  Breeching 


22'  1  ^  Plan    at    Footing 

Concrete  Chimney  with  Inner  Shell  Extending  Full  Height  of  Shaft 

To  create  a  draft  in  the  air  space,  in  order  to  protect  the 
outer  wall  from  high  temperatures  and  to  prevent  the  collection 
of  soot,  openings  in  the  outer  wall  are  made  at  the  base  of  the 
air  space.  The  inner  wall  is  made  as  thin  as  practicable  in  order 
to  minimize  unequal  expansion  and  is  4  in.  thick  for  its  entire 
height. 

The  thickness  of  the  outer  wall  of  the  chimney  illustrated 
reduces  from  12  in.  at  the  bottom  of  the  air  space  to  4  in.  at 


Concrete  Construction  133 

the  top  of  this  space  (beneath  the  cap).  In  nontapering  chimneys 
the  variation  in  thickness  is  made  by  offsets  on  the  inner  side,  but 
in  this  case  the  inner  side  is  vertical  and  the  reduction  is  made 
by  the  tapering  of  the  outer  side.  This  taper  was  given  by  the 
use  of  adjustable  steel  forms.  These  were  in  lifts  2  ft.  high, 
and  the  diameter  was  reduced  at  each  lift.  The  forms  were  found 
very  flexible,  and  the  same  ones  used  for  the  stack  were  made  to 
serve  also  for  the  enlarged  head,  or  cap. 

The  concrete  is  a  1:2:4  mix,  made  with  gravel  i  to  1  in.  in 
size.  It  was  hoisted  in  buckets  in  an  inside  tower,  which  carried 
the  working  platform.  The  reinforcement  consists  of  steel  rods  and 
hoops  in  each  wall,  the  vertical  rods  being  hooked  to  the  rods  in 
the  base  of  the  footing.  This  footing  is  built  directly  upon  a  stiff 
clay  formation,  no  piles  or  other  special  treatment  being  required. 

Results  of  Recent  Tests  in  the  Laboratory 

Results  of  Wood-Decay  Investigations 

Field  and  laboratory  studies  of  the  U.  S.  Forest  Service  indicate 
that  much  more  care  should  be  exercised  in  the  selection  of  timber 
and  in  the  construction  of  buildings  to  avoid  conditions  favorable 
to  decay.  Any  one  of  the  following  causes  may  result  in  rapid  de- 
terioration of  the  building:  (1)  Use  of  green  timber,  (2)  allowing 
the  timber  to  get  wet  during  construction,  (3)  allowing  the  timber 
to  absorb  moisture  after  the  building  is  finished  because  of  leaks 
or  lack  of  ventilation,  (4)  use  of  timber  containing  too  much  sap- 
wood,  (5)  use  of  timber  which  have  already  started  to  decay.  The 
avoidance  of  these  conditions  will,  as  a  rule,  prevent  decay.  In 
special  cases  preservative  treatment  is  necessary,  zinc  chloride  and 
sodium  fluoride  being  better  than  creosote  for  buildings. 

Studies  to  determine  the  extent  to  which  lumber  is  attacked  by 
fungi  while  seasoning  in  lumber  yards  are  being  continued.  Specific 
cases  were  studied,  showing  how  sound  lumber  is  infected  by  partly 
decayed  lumber  before  shipment  is  made.  Simple  rules  were  formu- 
lated for  restricting  the  spread  of  fungus  in  lumber.  Tests  to 
determine  the  effect  of  various  amounts  of  resin  in  the  southern 
pines  upon  their  durability  indicate  that  it  does  not  depend  directly 
upon  their  resin  content. 

About  1500  pieces  of  wood,  representing  50  different  species,  are 
under  test  to  determine  their  relative  durability.  At  the  end  of 


134  The  Engineer  in  Field  and  Office 

three  years,  all  of  the  conifers  with  the  exception  of  cypress,  red- 
wood, yew,  and  the  cedars,  have  decayed,  as  have  also  most  of  the 
hardwoods. 

Kiln-Dried  Douglas  Fir  Timbers  Tested 

Bending  tests  were  made  upon  four  kiln-dried  Douglas  fir  beams 
and  minor  specimens  cut  from  them  by  the  Forest  Products  Lab- 
oratory. Beams  1  and  2  were  dried  under  high  velocity,  low-super- 
heated steam,  at  a  temperature  of  225°  F.  for  a  day,  230°  F.  for  the 
succeeding  seven  days,  and  240°  F.  for  the  remaining  four  days. 
Beams  3  and  4  were  kept  at  a  temperature  of  220°  F.  throughout 
the  run,  the  steam  being  superheated  for  the  first  five  days,  when 
the  humidity  was  reduced  to  70%.  During  the  next  four  days  the 
humidity  dropped  gradually  to  25%,  where  it  was  maintained  during 
the  remaining  seven  days.  Beams  1  and  2  had  a  modulus  of  rupture 
of  6620  and  4910  Ib.  per  sq.in.  respectively,  and  beams  3  and  4  a 
modulus  of  rupture  of  4740  and  6160  Ib.  per  sq.in.  respectively.  All 
beams  failed  by  horizontal  shear  due  to  the  severe  checking.  The 
results  are  very  encouraging  for  the  development  of  the  process 
for  kiln  drying  Douglas  fir  beams  in  structural  sizes. 

Zinc  Borate  Retains  Fire-Resisting  Power 

The  Forest  Products  Laboratory  has  just  fire-tested  a  small 
shingle  roof  section,  painted  with  a  zinc  borate  paint,  which  has 
been  exposed  to  the  weather  for  nearly  three  years — other  shingles 
specially  treated  with  the  same  paint  being  used  as  a  control.  The 
results  show  that  the  paint  had  resisted  the  action  of  the  weather 
without  losing  its  fire-retarding  properties  to  any  marked  extent. 

White  Paint  Saves  Gasoline 

In  considering  the  effect  of  the  different  types  of  rays  of  which 
light  is  composed,  it  is  found  that  the  calorific,  or  heat-producing, 
rays  are  conducted  by  painted  or  finished  objects  in  widely  varying 
degree.  This  fact  should  be  studied.  When  black  or  dark-colored 
paints  have  been  used  in  painting  large  tanks  containing  light  dis- 
tillates, rapid  absorption  of  heat  takes  place,  and  considerable  losses 
by  evaporation  are  apt  to  occur.  White  or  light-colored  paint  should 


Laboratory  Work 


135 


therefore  be  used  for  the  finishing  coats  on  oil-storage  tanks. 
Paints  presenting  a  high  gloss  are,  moreover,  less  absorptive  of 
thermal  rays  than  those  presenting  a  matte  surface. 

RISE   IN   TEMPERATURE   OF   BENZINE   CONTAINED   IN    SMALL,   TANKS 

PAINTED  IN  VARIOUS  COLORS  (GLOSS  FINISH),  WHEN  SUBJECTED 

TO  HAYS  OF  CARBON  ARC  FOR  PERIOD  OF  15   MINUTES 


COLOR  Rise  in  Deg. 

Tin  plate   19.8 

Aluminum   paint    20.5 

White  paint 22.5 

Light   cream   paint.  . 23.0 

Light  pink  paint 23.7 

Light  blue  paint 24.3 


COLOR 

Light  gray  paint 

Light  green  paint 

Red  iron  oxide  paint 

Dark  Prussian  blue  paint.. 
Dark  chrome  green  paint.  . 
Black  paint  


Rise  in  Deg. 
26.3 
26.6 
29.7 
36.7 
39.9 
54.0 


Since  white  paints  faintly  tinted  have  given  substantially  the 
same  heat-reflecting  properties  as  white  paints,  the  former  should  be 
given  the  preference,  as  they  are  more  restful  to  the  eye  and  more 
durable  on  long-time  exposure. 

The  Lead  Content  of  a  Leaded-Zinc  Paint 

In  states  requiring  the  formula  to  be  shown  on  paint  packages, 
the  lead  content  of  all  oxides  excepting  the  lowest  (under  5%)  must 


80     90     100  PbS04\! 


ZnO 


Amounts  of  Leaded  Zinc  and  Sublimed  Lead  to  Use  for 
Desired  Lead  Content  of  Mix 

be  stated.  In  all  cases  where  the  lead  sulphate  is  actually  basic 
(Pb3S208),  this  is  properly  given  as  "basic  lead  sulphate."  On  the 
other  hand,  if  leaded  oxide  be  used  in  which  the  lead  content  is 


136  The  Engineer  in  Field  and  Office 

practically  all  present  as  normal  lead  sulphate  (PbSOJ,  the  pro- 
priety of  the  designation  may  be  subject  to  question. 

In  practice  it  is  often  necessary  or  desirable  to  increase  the  basic 
lead  sulphate  content  of  the  formula  over  that  present  in  the  leaded 
zinc  available  for  use.  Since  basic  lead  sulphate  (or  sublimed  lead) 
as  marketed  contains  about  5%  of  zinc  oxide,  calculation  of  the 
required  proportions  of  the  two  pigments  required  to  yield  the 
relative  percentages  is  a  rather  complicated  process.  The  accom- 
panying chart  will  furnish  the  required  information  at  a  glance. 

The  figures  to  the  left  indicate  the  percentages  of  leaded  zinc 
and  those  to  the  right  of  sublimed  lead  required  to  produce  the 
required  percentages  of  ZnO  and  PbS04  indicated  at  the  bottom 
of  the  chart.  The  four  diagonal  lines  represent  the  several  grades 
of  oxide.  To  find  any  desired  percentages  shown  in  the  bottom 
rows  of  figures,  using  any  of  the  oxides  shown,  follow  the  perpen- 
dicular line  to  its  intersection  with  the  proper  diagonal;  the  required 
percentages  of  that  oxide  and  sublimed  lead  will  then  be  found  on 
the  horizontal  line  to  the  left  and  right  respectively.  For  example: 
Desired  percentages  50  each,  using  a  35%  leaded  oxide.  The  50-50 
perpendicular  intersects  the  35%  diagonal  at  the  horizontal  line, 
which  indicates  at  the  left  76%  leaded  zinc,  and  at  the  right  24% 
sublimed  white  lead.  The  desired  percentages  will  therefore  be 
obtained  by  using  76  Ib.  of  the  former  to  24  Ib.  of  the  latter. 

Tinned  Copper  Is  No  Better  Than  Tin 
Plate  as  a  Roofing  Material 

The  unusual  and  interesting  corrosion  of  the  roofing  material  of 
the  Library  of  Congress  was  recently  investigated.  This  building 
has  been  covered  since  about  1893  by  tinned  sheet  copper  that  has 
become  covered  within  the  last  10  or  15  years  with  small  pits;  in 
many  cases,  these  pits  have  extended  completely  through  the 
sheet.  Such  a  condition  is  interesting,  particularly  in  view  of  the 
fact  that  Washington  is  uncommonly  free  from  smoke,  which  is 
ordinarily  understood  to  be  a  strong  accelerating  factor  in  corrosion. 
The  investigation  has  shown  that  the  corrosion  was  due  to  no 
accidental  inferiority  of  the  material,  but  that  it  is  to  be  considered 
as  characteristic  of  all  material  of  this  type.  It  appears,  therefore, 
that  tinned  copper  is  not  superior  in  any  way  to  tin  plate  for 
roofing  material  and  that  in  view  of  its  greater  cost  can  no  longer 
compete  with  it. 

Tinned  sheet  copper  is  used  also  for  containing  vessels  such  as 
milk  cans  and  for  fittings  such  as  troughs,  etc.,  for  soda  fountains 


Laboratory  Work  137 

and  breweries.  It  is  probable  that  such  articles  would  also  be  sub- 
ject to  pitting  corrosion  of  the  same  type  if  they  were  not  worn 
out  by  actual  abrasion  before  the  corrosion  had  proceeded  far. 

To  Prevent  Volume-Change  of  Wood 

Pieces  of  air-dried  wood  were  treated  in  a  variety  of  ways  to 
determine  the  best  methods  of  retarding  their  absorption  of  moisture 
from  the  air  and  loss  of  moisture  when  placed  in  dry  air.  Specimens 
were  treated  with  paraffin,  impregnated  with  sugar,  heated  at  high 
temperature,  painted,  varnished,  coated  with  bakelite,  impregnated 
with  creosote,  etc.  Curves  have  been  drawn  showing  the  relative 
shrinkage  and  swelling  which  took  place  in  these  boards  when 
exposed  over  a  period  of  a  year  to  atmosphere  containing  various 
humidities.  The  most  effective  results  were  secured  by  coating  the 
wood  with  paraffin.  Excellent  results  were  also  obtained  from  high 
temperature  treatments  and  by  impregnating  the  wood  with  sugar. 

Recent  Pressure  Tests  of  Welded  Joints 

Tests  recently  made  in  the  machine-construction  laboratory  of 
the  University  of  Kansas  show  that  the  joints  made  by  the 
oxyacetylene  method  develop  average  strengths  against  rupture  from 
internal  pressure  as  great  as,  if  not  greater  than,  those  which  may 

TESTS  SHOW  SUPERIORITY  OF  WELDED  CONNECTIONS 

Size  Pressure,  Lb.  per  Sq.In. 

Pipe  Type  Joint  At  Failure         Maximum  Nature  of  Failure 

2  in.         Welded  T  4400  4400  Tube  seam  split 

Welded  T  2200  2200  Leak  in  tube  seam 

Welded  T  4750  4750  Tube  seam  split 

Screwed  T  2350  2750  Sand  holes   in   fitting 

Screwed  T  500  2000  Sand  holes   in  fitting 

3  in.         Butt  weld  5300 

Butt  weld  4950  4950                      Tube  seam  split 

Butt  weld  4250 

Coupling  3950  3950                      Coupling  split 

Coupling  3400  4400                      Leak  In  coupling 

Welded  T  3500 

Welded  T  4250 

Welded  T  3505 

Screwed  T  350  2700                      Sand  holes  in  fitting 

Screwed  T  300  3100                      Sand  holes   in  fitting 

4  in.         Butt  weld  5100  Pipe  bulged 

Butt  weld  3250 

Coupling  300  3000  Leak    at    threads 

Coupling  750  2600  Leak    at    threads 

Welded  T  3850  5100  Leak  in  weld 

Screwed  T  1000  1950  Sand  hole  in  fitting 

be  ordinarily  expected  from  screwed  pipe  connections.  The  data 
given  in  the  accompanying  table  are  supplementary,  but  confirm- 
atory of  similar  figures  determined  about  a  year  ago. 


138 


The  Engineer  in  Field  and  Office 


The  results  indicate  that  the  strength  of  a  welded  pipe  connection 
is  practically  the  same  as  that  of  unwelded  pipe;  and  although  care- 
less welding  might  result  in  a  leaky  connection,  if  the  line  be  tested 
when  installed  it  should  be  immune  from  trouble  in  service. 


Special  Pump  Carries  Pressure  Over  5000  Pounds 

A  special  high-pressure  pump  of  simple  detail  was  designed  and 
built  for  this  work.  It  was  connected  to  the  specimens  under  test 
by  means  of  a  i-in.  copper  tube.  A  pressure  gage,  with  a  check 
valve  opening  toward  the  gage,  was  located  on  the  tube — the  valve 
being  necessary  to  steady  the  pressure  in  order  that  satisfactory 
readings  could  be  obtained,  because  some  of  the  samples  carry  pres- 
sures greater  than  5000  Ib.  per  sq.in.  before  failure. 

Dense  Wood  Gives  Nails  High  Values 

Tests  of  the  efficiency  of  various  types  of  wooden  joints  were 
made,  and  about  3000  nail-pulling  tests  were  completed  on  nails 
driven  into  twenty-five  different  species  of  American  timber.  While 
the  data  have  not  been  fully  analyzed,  it  appears  that  the  holding 
power  of  nails  has  a  definite  relationship  to  the  density  of  the 
wood,  and  that  there  is  practically  no  difference  in  strength  between 
a  solid  beam  and  a  wooden  beam  of  the  same  dimensions  made  of 
two  planks  nailed  together. 


Surveying 


139 


Practical  Hints  for  the  Surveyor 

Small  Motor  Cars  on  Precise  Level  Work 

Motor  driven  cars  with  flanged  wheels  for  use  on  railroad  tracks 
carry  the  outfit  used  by  the  United  States  Coast  and  Geodetic  Survey 
in  that  part  of  their  work  which  is  upon  railroad  rights  of  way. 

An  interesting  novelty  is  the  adding  machine  attached  to  one 
of  the  cars  for  recording  the  reports  of  the  parties  engaged  in 
precise  leveling.  A  rigid  frame,  which  holds  the  calculating  device, 
is  bolted  to  the  body  of  the  car.  The  operator  is  provided  with  a 
comfortable  cushioned  seat  over  the  wheel,  where  he  can  do  his 
work  conveniently.  The  added  reliability  and  greater  speed  of  the 
machine  for  noting  the  readings  of  the  level  rods  makes  it  a  valuable 
addition  to  the  equipment  of  parties  in  the  field. 

Another  car  carries  the  level,  the  tripod  being  securely  mounted 
upon  the  frame  of  the  motor  vehicle,  and  the  operator  standing 


Coast  and  Geodetic  Survey  Party  Carried  on  Light  Motor  Cars 

in  the  space  between  the  tracks.  Flat  trays,  or  hand  barrows,  on 
each  car  are  available  for  transporting  the  other  instruments,  tools 
and  personal  belongings  of  the  party. 

The  cars  are  light  in  weight,  with  frames  formed  of  steel  tub- 
ing, and  are  capable  of  traveling  at  a  good  speed  with  their  load 
of  instruments  and  passengers.  A  small  gas  engine  under  the 
frame  supplies  the  motive  power,  and  enables  the  party  to  reach  its 
field  of  operations  promptly  and  without  fatigue. 


140  The  Engineer  in  Field  and  Office 

Scale  on  Transit  Leg  Fixes  H.  I. 

An  easy  method  of  establishing  the  height  of  instrument  of  a 
transit  where  this  is  needed,  as  in  stadia  surveys,  is  to  fix  a  scale 
on  one  of  the  tripod  legs  by  which  the  length  of  plumb-bob  string 
and  hence  the  H.  I.  may  be  gaged.  The  procedure  of  placing  and 
using  the  scale  is  as  follows: 

Set  up  the  transit  over  the  hub  and  measure  the  H.  I.  carefully 
and  accurately.  Have  the  point  of  the  plumb-bob  just  touch  the  tack 
or  wherever  the  H.  I.  is  measured  from.  Swing  the  point  of  the 
bob  to  one  of  the  legs  of  the  transit  and  mark  this  point  on  the 
transit  leg.  By  similar  markings  scratch  a  scale  on  the  transit  leg, 
using  feet  and  tenths.  Then  at  any  time,  with  the  point  of  the 
bob  touching  the  tack  at  any  set-up,  the  H.  I.  may  be  read  directly 
on  the  leg  of  the  transit  by  swinging  the  bob  in  an  arc  and  reading 
the  point  of  the  bob.  This  will  give  results  to  the  nearest  hundredth, 
which  is  generally  close  enough. 

Set  Slope  Stakes  a  Foot  Outside 

A  deviation  from  the  usual  manner  of  setting  slope  stakes  for 
railroad  grading  has  been  used  successfully  by  the  writer.  Instead 
of  the  stake  being  driven  slanting  at  the  toe  of  the  embankment 
or  top  of  the  cut,  it  is  moved  out  one  foot  farther  and  driven  down 
straight.  Thus,  each  center-line  stake  is  practically  referenced  by 
two  hubs,  which  are  much  less  likely  to  be  displaced  than  if  set 
at  the  edge  of  the  slope.  If  the  contractor  is  advised  of  the  method 
of  setting  the  stakes,  it  has  proved  easy  and  convenient  for  him 
to  make  his  measurements  accordingly. 

Survey  Data  Made  Available  for  Field  Use 

The  engineer  engaged  in  land  surveying  is  often  handicapped 
in  the  field  by  finding  that  he  has  not  secured  enough  notes  to 
cover  the  work  to  be  done  or  by  finding  corners  described  by  the 
notes  at  hand  destroyed,  together  with  the  witness  trees,  and  that 
a  starting  point  some  distance  away  must  be  sought.  Again,  the 
surveyor  will  often  find  other  bearing  trees  than  those  described 
in  the  Government  records;  and  unless  he  has  the  notes  for  these 
trees,  they  are  worthless. 

First  copies  of  complete  section  notes,  giving  all  topography, 
are  secured  for  each  township  in  which  work  is  likely  to  be  done. 
By  having  the  topography,  a  tedious  search  for  a  corner  is  often 
done  away  with,  as  a  reference  measurement  can  be  made  from 


Surveying 


141 


some  stream  or  ridge.  These  section  notes  are  written  on  specially 
printed  blanks,  each  8£  x  11  in.  and  ruled  as  shown.  After  being 
copied,  all  sheets  are  carefully  checked. 

To  describe  corners  reestablished  or  reset,  typewritten  blanks 
are  prepared  for  section,  quarter-section  and  donation-land  claim 
corners.  These  are  filled  out  whenever  the  surveyor,  or  his  assist- 
ants, resets  or  establishes  a  corner. 


South  Bndr 

5HEET     | 
#               tbt,,*™  .C,«                 35  •    Z 

Tu>p.          26            S   R           5               w. 

rt-69'  47'  W 

Between  Section              35                           »"<*  Srrtion        2. 

2.OO 

7  80  . 

Va  r    1-4'  E"  . 

ZO    1  0 

Ravine-.   C.  S. 

31.00 

Top    of    nd<5e.    N  Sc  S 

•40.  OO 

Sri  Quarter  Post                                          from  wbicb  a 

Ye  1.  Oak.              24"           on.  Bean.  M.48*W.     132   IKs. 

W.     Ook                     18"                 Di,.BeBr..5.8r^.     487    ttfs 

57-00 

Top   o?-    n'd(5e.  Be'^n  4^  cfescend. 

63.00 

L?ove  Oak    opemo<fs,  enfer   pnairi>. 

75.00 

Ivfove   hillj  ^nfer   voll^u. 

76.2.0 

Trail     M.  ^   S 

80.00 

Sel  Post  Corner  to  Sections  2-3-34-35     from  which  a 

W.CbK.                             /<>"               Dia.  Bear,.  S2S°#  .       ?ff    //ft  . 

<?}(,.                             3"                 Dia.  Bear*.5ff/f'f.       6f      Hfi 

ft.  Offt                           S2.  '                  Di».  Bean.  f*Sf±  '&    /44      /*-*. 

tf.  Oaf-                              £"                  Dia.  Bear*.  H54'£.       73      fr$. 

Printed  Form  for  Section  Survey  Notes 

From  the  county  surveyor's  records  a  copy  is  made  of  any 
descriptions  of  corners  established.  This  search  of  records  is  kept 
uptodate,  and  the  data  are  transferred  to  the  township  portfolio  as 
soon  as  recorded.  All  reset  corner  sheets  are  filed  according  to 
township  and  range. 

Copies  of  all  of  the  donation-land  claim  notes  for  each  township 
are  secured,  and  these  are  bound  along  with  the  section  and  other 
notes  in  the  same  portfolio. 

Whenever  a  section  or  a  claim  is  subdivided,  a  record  is  made 
on  a  sheet  giving  character  of  corners  and  all  courses  and  distances. 


142  The  Engineer  in  Field  and  Office 

This  gives  the  surveyor  working  in  that  township  a  ready  reference 
to  the  work  already  done  and  many  times  saves  a  great  deal  of 
work  that  might  be  a  duplicate  of  some  already  surveyed. 

The  newspapers  are  watched;  and  whenever  descriptions  are 
published  for  Torrens  registration  work,  or  other  land  descriptions 
are  given,  they  are  clipped  out  and  pasted  to  blank  sheets  and  filed 
in  the  proper  township  portfolio. 

All  of  the  above  data  for  a  township  are  bound  in  covers  made 
of  heavy  drawing  paper  cut  to  a  size  9  x  12  in.  and  with  a  back  1  in. 
in  width.  On  this  cover,  at  the  top,  are  printed  in  large  letters 
the  township  and  range  numbers. 

In  practically  all  of  the  Western  States,  small  lithographs  of 
each  township,  about  6  in.  square,  can  be  obtained,  and  one  for  the 
proper  township  and  range  is  cut  down  to  a  minimum  size  and 
pasted  on  the  portfolio  cover  below  the  title.  This  plat  shows  the 
streams,  sections  and  donation-land  claims  and  acts  as  a  key  map 
for  the  surveyor. 

To  facilitate  the  work  of  securing  a  meridian,  either  by  means 
of  a  solar  instrument  or  by  a  direct  observation,  the  latitude  of 
each  tier  of  sections  in  the  township  is  figured  and  written  on  the 
right-hand  side  of  the  cover  map,  each  latitude  opposite  the  section 
line  for  which  it  was  computed.  The  longitude  for  the  nearest  10' 
is  also  shown  in  its  correct  position  on  the  plat. 

A  portfolio  of  the  size  described  can  be  easily  folded  in  the 
middle  and  held  with  two  rubber  bands,  so  as  to  be  carried  in  the 
surveyor's  pocket. 

By  having  with  him  the  portfolio  of  notes  for  the  township  in 
which  he  is  called  to  work,  the  surveyor  has  as  complete  a  record 
as  it  is  possible  to  have  to  enable  him  to  reset  or  establish  corners. 
He  also  has  other  data  of  work  done  that  will  be  of  great  value. 
With  these  notes  he  can  go  from  one  job  to  another  in  the  same 
township  without  first  having  to  send  or  go  to  the  office  for  further 
notes. 

If  surveyors  in  the  same  locality  could  be  induced  to  exchange 
notes  of  surveys,  all  data  on  reset  corners  or  subdivision  work  could 
be  kept  up  to  date,  and  each  one  would  have  the  data  in  shape  for 
field  reference. 

Field  Repair  for  Broken  Steel  Tape 
From  time  to  time  there  appear  in  the  engineering  magazines, 
methods  of  repairing  a  steel  tape  in  the  field.     Most  of  them  will 
slip  without  entirely  pulling  apart  and  are  a  constant  source  of 
worry.     The  method  outlined  below  is  guaranteed  not  to  slip. 


Surveying  143 

Heat  each  of  the  broken  ends  with  a  match,  drawing  the  temper 
for  about  a  quarter  of  an  inch,  so  that  it  will  bend  without  breaking. 
Slip  the  end  between  the  blades  of  your  knife  and  bend  to  a  right 
angle.  Then  proceed  to  mend  it  by  splitting  a  small  stick  and 


Ends  &f 
Tape  berrf- 


This  Repair  Makes  Slipping  Impossible 

making  notches  in  one  half  to  take  the  bent  ends.  Wrap  with 
a  piece  of  twine  after  tapering  the  ends  of  the  stick  so  that  it 
will  not  catch  in  the  brush.  Then  proceed  to  chain — and  don't 
worry  as  to  whether  your  tape  has  stretched  half  an  inch  at  the 
splice. 

Wedge-Shaped  Stake  Better  than  Straight  Stake 

Contractors  are  sometimes  put  to  a  great  deal  of  inconvenience 
and  are  forced  to  lose  time  and  make  mistakes  by  the  engineer's 
stakes  being  lost  or  displaced.  The  ordinary  stake  as  used  by  the 
engineer  is  so  made  as  to  be  very  easily  knocked  out  of  position. 
This  defect  is  due  to  the  way  in  which  the  stake  is  sharpened. 

The  left-hand  sketch  gives  the  form  of  stake  ordinarily  used — 
a  straight  stick  sharpened  with  a  short  slope  from  both  sides.  When 
such  a  stake  is  driven,  the  point  is  the  only  part  firmly  seated,  while 
the  body  of  the  stake  is  as  large  just  above  the  point  as  the  rest  of 
the  way  up,  so  that  the  stake  just  stands  in  a  hole  made  by  the  point. 
This  shape  accounts  for  the  ease  with  which  most  stakes  are  dis- 
placed. However,  if  the  stake  be  made  of  the  form  shown  at  the 
right,  it  will  be  found  to  give  much  greater  satisfaction.  This  stake 
is  sharpened  only  on  one  side,  but  the  slope  extends  three-fourths 
the  length  of  the  stake.  When  driven  into  the  earth,  the  stake  is 
held  very  much  more  firmly  than  is  the  other  kind,  because  the  taper 
is  much  longer  and  therefore  the  earth  adheres  to  a  greater  length 
of  the  stake.  It  is  very  difficult  to  draw  this  type  of  stake  out  of 
the  earth  when  once  driven  in.  If  exposed  to  traffic,  as  in  the  case 


144  The  Engineer  in  Field  and  Office 

of  streets  and  highways,  the  stakes  are  sometimes  broken  off  at  the 
ground,  the  stake  breaking  before  it  pulls  up.  In  this  case  the  point 
is  still  in  position  and  can  be  found  and  replaced. 


V 

Wrong  and  Right  Way 

A  test  of  these  two  types  of  stakes  was  made  on  a  highway  on 
which  the  traffic  was  very  heavy.  The  following  was  the  result: 
Equal  numbers  of  the  two  kinds  of  stakes  being  used,  under  equal 
exposure,  14%  of  the  first  type  were  entirely  lost,  while  only  2i% 
of  the  other  were  lost. 

Setting  Grade  Stakes  for  Bridge  Approach 

In  grading  and  repaving  the  curved  and  raised  approaches  to  the 
Cambria  St.  bridge,  Philadelphia,  the  street  surface  and  curb  and 
gutter  heights  were  first  worked  out  by  the  help  of  a  contour  plan 
drawn  to  a  scale  of  4  in.  to  the  foot,  with  0.1-ft.  contours.  To  trans- 
fer the  final  design  to  the  ground  the  method  adopted  was  laying  out 
a  system  of  points  on  10-ft.  squares,  finding  the  grades  of  these 
points  by  interpolating  between  contours,  and  setting  and  marking 
stakes  accordingly.  The  labor  of  setting  these  stakes  was  not  great, 
and  the  resulting  pavement  surface  corresponded  more  nearly  to  the 
predetermined  one  than  could  have  been  obtained  by  the  eye  or  by 
the  use  of  level  boards. 

Brass  Tack  in  Lead  Wool  as  Instrument  Point 

Contractors*  engineers  are  often  obliged  to  set  points  on  finished 
concrete  in  giving  lines  and  grades  for  construction  work.  Chalk 
and  pencil  marks  are  soon  obliterated,  chisel  cuts  are  hard  to  find 
or  easily  chipped  and  rendered  indistinct  unless  the  concrete  has 
thoroughly  hardened,  and  in  some  cases  cannot  be  used  because  they 
would  constitute  a  permanent  defacement.  A  brass  tack,  on  the 
other  hand,  always  stays  bright  even  if  set  in  a  floor,  and  is  easily 
seen. 


Draftsmen's  Kinks  145 

The  method  which  the  writer  has  found  convenient  for  setting 
such  tacks  is  to  drill,  preferably  when  the  concrete  is  one  or  two  days 
old,  a  small  hole  an  inch  or  more  into  the  surface.  This  hole  is  then 
packed  full  of  lead  wool,  into  which  a  large  brass  tack  with  a  small 
head  is  driven.  Such  points  may,  of  course,  be  used  either  as  transit 
points  or  as  benchmarks  in  horizontal  or  vertical  surfaces. 

Draftsmen's  Kinks 

Mounting  Blueprints  on  Muslin 

Maps  and  plans  on  paper  frequently  fail  by  tearing  or  wearing 
through  due  to  hard  usage.  Sensitized  cloth  has  been  employed  more 
or  less  successfully,  but  it  has  its  disadvantages,  due  to  the  fact 
that  the  cloth  is  generally  of  poor  quality  and  tears  easily.  Further- 
more, if  allowed  to  stand  for  some  time  before  being  used,  the  sensi- 
tizing solution  causes  the  cloth  to  rot.  A  much  better  and  not  too 
difficult  method  is  to  mount  the  paper  print  upon  cloth.  Large  wall 
maps  hang  better  and  are  much  less  liable  to  be  harmed  when 
mounted  in  this  way  than  when  left  unmounted. 

The  print  should  be  made  upon  "medium"  weight  paper  unless  an 
extra-strong  sheet  is  desired.  While  the  printing  is  going  on,  a 
helper  can  prepare  the  cloth  backing.  Unbleached  muslin  that  sells 
at  about  lOc.  per  yard  is  ordinarily  used.  Select  a  smooth  board, 
larger  than  the  size  of  the  print  to  be  mounted,  and  clean  it  thor- 
oughly. A  drafting  board  or  the  top  of  a  drafting  table  is  excel- 
lent for  this  purpose — provided  it  is  not  cedar,  for  cedar  will  stain 
the  prints.  Fasten  the  cloth  on  this  board  with  4-oz.  carpet  tacks 
spaced  about  2  in.  apart,  and  driven  only  partially  home  so  that  they 
may  be  easily  pulled. 

Tack  one  edge  of  the  cloth  down,  stretching  it  smooth  but  not  too 
tightly,  for  the  paper  contracts  on  drying-out  and  will  crack  if  there 
is  not  enough  "give"  to  the  cloth.  Follow  around  the  edge  of  the 
cloth  until  it  is  completely  tacked  down.  It  should  now  present  a 
smooth  surface  and  is  ready  for  the  mount.  If  many  prints  are  to  be 
mounted,  it  may  be  an  advantage  to  set  several  boards,  end  to  end, 
and  tack  the  cloth  over  their  entire  length.  In  this  manner  consid- 
erable cloth  can  be  saved. 

After  washing  the  prints  they  should  be  taken  from  the  final 
bath  and  the  excess  water  blotted  from  both  sides  with  a  dry  towel 
or  cloth.  If  the  print  has  been  made  some  time  previously  and  is 
dry,  immerse  it  in  water  for  two  or  three  minutes — or  until  it  is 
thoroughly  wet — then  remove  it  and  proceed  as  above.  Lay  the 


146  The  Engineer  in  Field  and  Office 

print  carefully  down  on  a  clean  table  top  or  board  and  apply  a  thin 
but  even  coating  of  paste,  making  sure  that  the  edges  and  corners 
have  received  their  share.  The  paste  should  be  a  fresh,  stiff  corn- 
starch  paste  or  fresh  wall-paper  paste.  Glue  or  library  paste  is 
unsatisfactory  and  should  not  be  used. 

Pick  the  paper  up  carefully  and  while  one  man  holds  an  edge 
above  the  cloth,  the  other,  on  the  opposite  side  of  the  table,  should 
take  the  lowered  edge  and  paste  it  down — using  a  stiff  kalsomine  or 
large,  flat  paint  brush.  Brush  the  paper  down,  working  away  from 
the  body  with  short  strokes,  the  helper  slowly  lowering  his  end. 
In  this  manner  the  brush  will  drive  out  all  air  bubbles  and  make  a 
uniformly  smooth  job.  After  the  paper  is  brushed  fast,  take  a  stiff 
clothes  brush  and  gently  pat  the  edges  down,  thus  insuring  a  perfect 
contact  at  the  vulnerable  point. 

The  print  should  dry  slowly  in  an  even,  moderate  temperature 
for  at  least  36  hours.  The  print  can  then  be  trimmed.  If  a  Van 
Dyke  print,  corrections,  if  any,  should  be  applied  at  this  time,  using 
ordinary  black  drawing  ink. 

Ruling  with  Common  Ink  Saves  Time 

In  making  scale  sketches  on  desk  designing  sheets  for  direct  trac- 
ing by  the  draftsman,  one  engineer  finds  it  a  great  convenience  to 
use  ordinary,  in  place  of  india,  ink.  This  requires  a  german-silver 
ruling-pen,  such  as  is  made  for  bookkeepers'  use.  A  time  saving 
results  from  the  fact  that  when  the  pen  is  laid  aside  with  its  ink 
filling  it  will  not  dry  out,  but  will  be  ready  for  instant  use  even  after 
a  quarter  or  half  an  hour. 

Drawing  the  sketches  in  ink,  rather  than  pencil,  is  far  easier 
for  the  tracer  as  well  as  being  safer  against  errors  in  tracing.  The 
method  applies  to  a  great  many  parts  or  objects  of  such  simple 
character  (or  to  be  shown  so  generally)  that  no  fuller  detailing  is 
needed  than  the  designer's  sketch  contains.  However,  lines  as  fine  as 
may  be  desired  may  be  drawn. 

Reducing  the  Cost  of  Plotting  Stadia  Notes 

By  plotting  stadia  notes  on  separate  sheets  such  as  are  shown 
in  the  accompanying  sketch  and  tracing  the  finished  map  from  these 
sheets,  the  cost  of  plotting  stadia  notes  has  been  materially  reduced 
and  the  speed  almost  doubled.  Plotting  topography  by  this  method 
becomes  independent  of  drafting-room  equipments,  a  lead  pencil 
being  the  only  tool  required. 


Draftsmen's  Kinks 


147 


The  ordinary  method  of  procedure  is  to  sketch  the  topography  in 
heavy  pencil  lines  and  either  paste  the  sheets  together  for  the  drafts- 
man or  send  them  to  him  separately.  The  sheets  are  placed  under 
the  tracing  cloth,  and  the  finished  tracing  is  made  directly  from 
them.  The  paper  used  for  ordinary  work  is  84  x  11  in.  in  size. 


'-& 


Speeds  Up  Interpolation — Increases  Accuracy 

Using  a  scale  of  100  ft.  to  the  inch,  a  length  of  1000  ft.  and  a  width 
of  600  ft.  of  topography  may  be  plotted  on  each  sheet.  Topography 
may  be  plotted  by  surveyors  on  rainy  days,  either  in  the  field  or  in 
the  office,  several  men  working  independently  on  separate  parts  of 
the  notes.  It  is  remarkable  how  much  the  use  of  a  graduated  paper 
speeds  up  the  interpolation  of  contours  and  increases  the  accuracy 
of  scaling. 


148 


The  Engineer  in  Field  and  Office 


Folding  Drawing  Trestle 

A  drawing-table  trestle  which  will  take  up  a  space  only  4  in. 
square  and  4  ft.  long  when  stored,  would  prove  a  great  convenience 
to  many  engineers  who  do  not  need  a  drawing  table  continually, 
or  whose  work  sometimes  requires  one  where  ordinarily  there  would 


Notches  ±0  receive 
•Top  cf  Legs 


Tire 
Bon- 


Adjustment  for  Height  and  Slope  of  Board  Easily  Made 

not  be  proper  facilities.  The  construction  illustrated  in  the  accom- 
panying drawing  has  been  used  for  the  past  two  years  and  has 
proven  to  be  convenient,  rigid,  light  and  capable  of  being  easily 
transported  and  stored  in  a  small  space. 

The  following  is  a  bill  of  necessary  materials: 
2 — I  x  H-in.  hardwood  strips,  4  ft.  1  in.  long,  front  legs. 
2 — f  x  H-in.  hardwood  strips,  3  ft.  10  in.  long,  back  legs. 
1 — I  x  4-in.  hardwood  board,  34  in.  long,  top  piece. 
6 — 1-in.  shothead  screws. 
2 — 2-in.  tire-bolts  and  washers. 
1 — 2i-in.  tire-bolt  and  washer. 

1 — f-jn.  band-iron  strip,  7  in.  long,  drilled  for  screws  on  6-in.  cen- 
ters and  one  hole  cut  out  to  serve  as  a  hook. 


Draftsmen's  Kinks  149 

1 — I-in.  band-iron  strip,  4  in.  long,  drilled  for  screws  on  3i-in. 

centers. 

The  method  of  assembling  is  perhaps  sufficiently  illustrated  in 
the  drawing.  By  placing  the  top  ends  of  the  longer  legs  in  the  dif- 
ferent notches,  which  must  be  gained  in  the  top  piece,  the  top  of 
the  trestle  can  be  made  either  level  or  sloping,  and  the  height  ad- 
justed from  34  in.  to  42  in. 

How  To  Waterproof  Drawings 

A.  Give  the  drawing  several  light  coats  of  white  shellac,  dis- 
solved in  grain  alcohol,  letting  each  coat  dry  before  the  next  is 
applied.     Orange  shellac  and  even  wood  alcohol  may  be  used;  but 
the  "white"  or  bleached  shellac  is  preferable  and  wood  alcohol  is 
objectionable  because  of  its  injurious  effect  on  the  eyes. 

B.  Give  the  drawings  several  light  coats  of  "Zapan"  varnish, 
which  is  made  of  scrap  trimmings  of  clear  sheet  celluloid  dissolved 
in  acetone  and  is  produced  by  several  Eastern  chemical  factories 
and  firms  manufacturing  celluloid  articles. 

C.  When  a  heavier  protective  covering  is  desired  than  A  or  B 
will  provide,  the  drawing  may  be  made  wet  with  the  thin  celluloid 
varnish  and  pressed  down  evenly  on  a  sheet  of  thin  sheet  celluloid, 
then  allowed  to  dry.    This  process  gives  a  beautiful  clear  mounting 
with  0.01  in.  of  celluloid  on  the  face. 

D.  Drawings  may  be  made  waterproof  with  melted  paraffin  wax, 
which  is  applied  with  a  flat  bristle  brush.    The  drawing  is  then  put 
between  two  sheets  of  blotting  paper,  and  a  hot  sad-iron  is  passed 
over  the  upper  blotter,  thus  causing  the  paraffin  to  be  distributed 
more  evenly  and  the  surplus  to  be  absorbed  by  the  blotting  paper. 
The  blotters  must  be  removed  before  they  cool.    If  the  wax  is  thick 
and  white  over  any  part  of  the  drawing  or  print,  sponge  it  off  with 
benzine. 

E.  Drawings  may  be  paraffined  by  dissolving  the  paraffin  wax 
in  benzine  and  then  thoroughly  painting  the  drawing  with  this 
liquid  or  passing  the  drawing  through  a  bath  and  hanging  it  up  to 
dry. 

Some  of  the  solvents  mentioned  are  very  inflammable  and  even 
explosive,  so  all  open  lights  should  be  kept  away  from  them.  Some- 
times they  affect  certain  people  injuriously;  accordingly,  such  work 
should  be  done  only  in  a  well-ventilated  room,  with  a  fan  to  keep 
fresh  air  moving  over  the  work. 


150 


The  Engineer  in  Field  and  Office 


Make  This  to  Carry  Your  Drawings 

It  is  customary  for  drafting  rooms  to  place  their  drawings, 
either  every  night  or  once  a  week,  in  a  vault  for  safe  keeping.  The 
device  shown  in  the  illustration  has  proved  satisfactory  for  carrying 
the  drawings.  It  is  easy  to  make,  two  pieces  of  white  pine  A, 
37  x  11  x  I  in.,  two  black  japanned  door  pulls  B  and  one  piece  of  un- 
bleached cloth  C,  37  x  30  in.,  being  fastened  together  in  the  manner 


A  Convenience — and  Takes  Up  No  Room 

shown.  If  desired,  a  small  hook  and  eye  may  be  attached  at  each  end 
of  the  wood  crosspieces  to  hold  them  together  and  prevent  the  loss 
of  drawings  when  the  carry-all  is  laid  down. 

Plot  Offsets  with  Frame  and  Sliding  Piece 

A  device  for  mapping  survey  notes,  consisting  of  a  fixed  frame 
for  longitudinal  measurements  and  a  sliding  scale  for  offset  dis- 
tances, is  shown  in  the  accompanying  sketch.  The  rectangular 
frame  is  made  of  1-in.  sheet  iron.  The  scale  along  the  left-hand  edge 
can  be  stamped  on  or  glued  on.  The  sliding  scale  can  be  readily 
made  from  an  old  celluloid  triangle.  To  orient  the  scales,  the  center 
point  at  the  top  of  the  hollow  rectangle,  which  is  opposite  the  zero 
of  the  longitudinal  scale,  is  set  over  one  transit  point  and  the  zero 
of  the  sliding  scale  over  the  other.  The  edge  of  the  sliding  scale 
will  then  always  be  at  right  angles  to  the  base  line. 


Draftsmen's  Kinks 


151 


It  may  be  seen  that  any  survey  made  by  pluses  and  right-angle 
offsets  from  a  base  line,  such  as  railroad  station-map  surveys,  can 
be  readily  plotted  with  the  device.  It  might  be  convenient  to  provide 


Pluses  and  Offsets  Easily  Plotted  by  This  Device 

four  scales  by  starting  one  from  each  of  the  four  corners  of  the 
steel  frame,  and  making  two  sliding  pieces  with  a  scale  on  each  face. 
Both  a  50-ft.  and  a  100-ffc.  scale  would  be  used  frequently. 

Keeping  Tab   on   Revised   Drawings 

In  supervising  a  large  concrete  building  job  at  some  distance 
from  the  main  office  where  the  detail  plans  are  made,  there  is  ever 
present  a  danger  that  the  latest  plans  may  not  be  used  by  the  field 
superintendent  and  the  construction  gang.  The  structural  plans  for 
a  concrete  building  are  seldom  completed  when  bids  are  called  for, 
the  usual  practice  being  to  have  the  footing  design  and  column 
schedule  completed  at  the  time  so  that  the  material  can  be  ordered 
and  work  started  without  delay  after  awarding  the  contract.  The 
detailing  of  the  superstructure  is  usually  carried  on  slightly  ahead 
of  the  construction  work,  necessitating  the  issuance  of  several  pro- 
gress prints  of  the  same  plan. 


152 


The  Engineer  in  Field  and  Office 


It  has  been  found  worth  while  to  issue  a  memorandum  at  the  end 
of  each  week,  giving  the  date  of  the  latest  print  of  each  plan  issued. 
These  memo's  are  typewritten  on  standard  specification-size  sheets. 
Blueprints  are  made  from  them  and  are  sent  to  the  superintendent 
and  contractors,  who  post  them  in  the  various  field  and  main  offices. 
Blueprints  are  used  since  they  are  more  conspicuous  and  more  apt 
to  be  regarded  as  a  part  of  the  plans  than  are  carbon  copies.  The 
following  form  is  used : 

PLAN  MEMORANDUM 

Date 

Building  for  "A.  B.  Co."     City 

Post  in  a  Conspicuous  Place. 

The  latest  prints  of  plans  to  be  used  are  dated  (with  rubber  stamp)  as 
follows : 

Sheet   No Description Date 

These  memoranda  are  sent  out  on  Saturday  of  each  week,  except 
when  only  one  or  two  revised  prints  have  been  sent  out  since  the 
last  memorandum. 

Each  time  a  sheet  is  revised  or  some  new  feature  is  added,  a  note 
(with  date  made)  is  placed  on  the  tracing  in  a  space  provided  in 
the  title  of  the  sheet.  In  addition  to  this  each  print  is  marked  with 
rubber  stamps,  as  shown  herewith. 

The  upper  stamp  calls  attention  to  the  fact  that  the  print  con- 
tains some  revision  or  addition  not  shown  on  previous  prints,  and 
by  referring  to  the  revision  list  (in  title)  the  extent  of  the  change 


REVISED  PRINT 

Destroy  all  prints 

previously  sent  you 


THIS  PRINT  MADE 

Dec.  20  1917 


Prints  Marked  ivlth  These  Two  Stamps 
Upper  stamp  is  3|  x  1  in. ;  lower  is  2J  x  g  in. 


can  be  found  at  once.  If  the  print  bears  a  later  date  than  the  one 
noted  for  this  sheet  on  the  memorandum  sheet  posted  in  the  field 
office,  the  memo  is  revised  by  the  superintendent  to  show  the  date 
of  the  latest  print.  In  this  way  a  careful  record  of  the  latest  prints 
is  kept,  and  anyone  not  familiar  with  all  the  details  of  the  work  can 


Filing  Data  153 

quickly  find,  by  referring  to  the  memorandum  sheet,  which  prints 
should  be  used  for  construction  work,  and  thus  costly  errors  due 
to  use  of  superseded  and  void  plans  are  avoided. 

Simple  and  Effective  Methods  for  Filing 
Engineering  Data 

Lantern  Slides  Should  Be  Indexed  and  Filed 

Perhaps  the  most  customary  method  of  filing  lantern  slides  is  in 
the  wooden  boxes  which  are  on  the  market  for  that  purpose.  These 
are  of  varying  capacities,  containing  from  50  to  200  slides.  Each 
slide  has  its  individual  compartment  formed  by  cardboard  parti- 
tions inserted  in  grooves  in  the  sides  of  the  box.  When  the  hinged 
cover  is  raised  the  rim  of  the  long  way  of  the  box  is  seen  to  be 
divided  off  by  the  indentations  made  by  the  grooves.  Each  division 
marks  a  slide  compartment,  and  it  is  convenient  to  number  these  di- 
visions on  the  front  rim  with  small  india-ink  figures  to  correspond 
with  the  numbers  of  the  slides.  On  either  end  of  the  exterior  of  the 
box  the  inclusive  numbers  should  be  indicated.  As  the  slides  are 
numbered  in  the  order  of  their  accession  no  duplication  occurs,  and 
the  boxes  may  be  arranged  uniformly  and  neatly  in  numerical 
sequence. 

Each  slide  when  received  is  numbered  in  india  ink  upon  the 
thumbspot.  An  indelible  ink  is  especially  necessary  for  this  since 
the  thumbspot  marks  the  position  for  the  operator's  thumb  when 
he  inserts  the  slide  in  the  lantern,  and  ordinary  ink  would  smut. 
Close  beside  the  thumbspot  there  should  be  another  small  sticker 
which  is  left  blank  so  that  those  slides  selected  for  a  lecture  may  be 
lightly  numbered  in  pencil  to  insure  their  temporary  sequence.  On 
a  narrow  strip  pasted  across  one  end  of  the  slide  the  brief  title 
should  be  written. 

To  avoid  misplaced  slides  they  should  be  arranged  so  that  they 
face  the  left-hand  end  of  the  box  and  have  the  thumbspots  at  the 
top,  thus  facilitating  ready  detection  of  any  discrepancy  between 
a  slide  number  and  that  of  its  compartment.  Similarly,  in  the  trav- 
eling case,  this  arrangement  is  a  convenience  since  it  enables  the 
operator  to  seize  the  slide  with  its  face  toward  him  and  by  a  turn 
of  the  wrist  to  invert  it  in  readiness  for  insertion  in  the  lantern. 

As  received  the  slides  are  listed  under  the  headings  Slide  Num- 
ber, Title,  Owner,  Date  and  Origin,  on  lettersize  sheets  secured  be- 
tween cardboard  covers  by  brass  binding  pins.  Following  this  ac- 
cession list  and  separated  from  it  by  a  colored  sheet  is  the  place  or 


154 


The  Engineer  in  Field  and  Office 


subject  list.  To  each  place  of  which  there  are  descriptive  slides 
a  page  is  devoted  upon  which  the  numbers  and  titles  are  listed. 
For  theoretical  features,  diagrams,  tabulations,  etc.,  a  sheet  headed 
Miscellaneous  is  provided,  from  which,  however,  any  of  the  items 
may  be  segregated  upon  separate  subject  sheets  when  desirable. 
These  place  and  subject  sheets  are  assembled  in  alphabetical  se- 
quence. 

A  heavy  manila  envelope,  say  9x5  in.,  pasted  on  the  inside  of 
the  back  cover,  affords  an  opportunity  for  the  filing  of  lists  of  slides 
temporarily  withdrawn  from  the  file.  While  these  lists  may  be  mere 
memoranda  to  be  destroyed  when  the  slides  have  been  checked  off 
as  returned,  it  is  preferable  to  typewrite  them  in  permanent  form 
upon  sheets  headed  with  the  name  of  the  borrower,  the  title  of  the 
talk,  the  place,  date,  etc. — since  such  lists  have  a  suggestive  value 
in  the  preparation  of  further  illustrated  talks.  Before  the  slides  are 
returned  to  their  compartments  the  pencil  numbers  added  by  the 
borrower  should  be  transferred  to  the  loan  list,  to  show  the  sequence 
in  which  the  slides  were  used,  and  then  erased  from  the  slides. 

Blueprint  Table  has  Several  Functions 

The  table  shown  in  the  sketch  combines  the  functions  of  the 
storage  can,  the  scissors  and  the  yardstick.  The  roll  of  paper  is 


puffing  Edge 


_gi  

r 
k 

i 

==a=- 

^T^^--^--^^ 

i 

o 

r 


-±Slot -for  Paper 

•   ^L-j^,  *L    t/  ff^tlSJ** 


Blueprint  Table  Saves  Time  and  Paper 

stored  in  -the  box  at  the  end  and  pulled  out  through  the  slot,  meas- 
ured with  the  foot  marks  and  torn  off  on  the  cutting  edge.     Less 


Filing  Data  155 

than  i  in.  of  paper  is  spoiled,  and  this  only  when  the  strip  is  left 
exposed  for  a  considerable  length  of  time.  At  least  this  much  is 
ordinarily  wasted  by  excess  cutting.  The  left-hand  box  is  used  for 
odd  sheets  of  paper,  but  may  be  slotted  and  used  for  a  different 
grade  of  paper. 

Pamphlets  Indexed  and  Filed  by  Simple  System 

Pamphlets  in  great  variety,  principally  bulletins  and  reports,  are 
available  in  constantly  increasing  number  and  comprise  a  very  im- 
portant class  of  current  literature.  The  value  of  the  information 
which  they  contain  is,  however,  considerably  lessened  if  they  are 
not  indexed  and  filed  in  a  manner  which  facilitates  easy  reference  to 
their  contents.  Indexing  and  filing  pamphlets  by  the  following  plan 
has  been  found  to  be  a  simple  matter  and  to  give  satisfactory  results 
as  to  convenience  of  reference. 

As  soon  as  convenient  after  receiving,  the  pamphlet  is  read,  or  at 
least  inspected  to  ascertain  the  character  and  scope  of  its  contents. 
As  this  is  being  done  such  index  cards  as  are  thought  desirable  are 
written.  For  this  purpose  a  very  thin  3-in.  x  5-in.  card  ruled  hori- 
zontally and  made  up  in  pads  is  used.  For  this  and  general 
notebook  purposes  it  is  convenient  to  carry  a  number  of  these  cards 
in  a  loose-leaf  notebook. 

The  index  cards  are  then  placed  together  in  the  pamphlet  until  it 
proves  convenient  to  assign  serial  numbers  to  the  pamphlets  for 
filing  purposes.  A  simple  record  of  the  pamphlet  numbers  assigned 
is  kept  by  filing  with  the  pamphlets  a  6-in.  x  9-in.  card  on  which 
the  last  serial  number  assigned  is  noted  each  time.  It  has  been 
found  most  convenient  to  place  the  numbers  on  the  upper  right-hand 
corner  of  the  index  cards  and  on  the  upper  left-hand  corner  of  the 
pamphlet  cover.  This  numbering  may  be  done  by  hand,  though  a 
numbering  machine  does  the  work  more  neatly  and  quickly.  A  very 
satisfactory  substitute  is  a  rubberstamp  numberer,  similar  in  con- 
struction to  the  familiar  band  dater. 

The  pamphlets  are  then  filed  in  the  order  of  their  serial  numbers 
from  left  to  right  on  shelves  or  in  bookcases.  A  decidedly  neater 
appearance  is  given  the  collection  when  filed  in  pamphlet  boxes.  It 
will  be  found  a  simple  matter  to  make  up  these  boxes  as  needed  after 
the  construction  indicated  in  the  illustration.  Where  heavy  card- 
board is  used,  the  bending  is  facilitated  by  making  a  very  light 
knife  cut  on  the  fold  lines.  A  neat  appearance,  as  well  as  a  stronger 
box,  results  when  the  exposed  edges  are  bound  with  gummed  cloth 
tape  or  the  gummed  paper  strips  used  in  binding  lantern  slides. 


156 


The  Engineer  in  Field  and  Office 


Each  pamphlet  box  should  carry  a  serial  number  as  well  as  a  number 
corresponding  to  the  highest  serial  number  of  the  pamphlets  that  are 
filed  in  the  box. 


/ 

,-7 

V 

Cv 

t  , 

/ 

1 

X 

-- 

: 

* 
^ 

i 

* 

•^ 

; 

_} 

'__2 

k.-      .      -  -  /£?—  ^  sj 

••     lyp    -• 


.•"White  pine 
_—  ^~  >-L_^_  ___  Binding-'''^" 

"T" 

Highest  serial  number  of  pamphlets  filed  in  box  -• 

Serial  number  of  box --^          -^ 

M 

No.  19  Wire  nails,  j  long,  flat  head-- •.&.-•:?<£ 
Filing  Box  Is  Easily  Made 


The  filing  of  pamphlets  by  arbitrary  serial  numbers  is  far  more 
simple,  elastic  and  generally  satisfactory  than  any  attempt  to 
classify  or  group  these  publications  according  to  their  subject 
matter.  And  any  system  of  indexing,  to  be  satisfactory,  demands 
the  personal  attention  of  the  person  who  is  to  make  use  of  it,  as  the 
average  office  help  cannot  be  expected  to  do  indexing  of  this  sort 
with  any  satisfactory  degree  of  intelligence. 


Filing  Data  157 

Index  of  Details  for  a   Structural  Office 

Well  executed  and  consistent  plans  are  the  prime  indication  of  a 
good  design  in  all  classes  of  structures ;  especially  in  building  work, 
which  involves  a  great  many  different  types  for  the  great  variety 
of  uses.  This  makes  standardization  of  details  and  design  somewhat 
more  difficult  than  for  the  superstructures  of  highway  and  railroad 
bridges,  but  unless  standardization  is  kept  in  mind  constantly,  the 
cost  of  making  the  design  is  quite  likely  to  be  so  high  as  to  show 
little  profit;  and  at  the  same  time  the  resulting  structure  may  be 
more  costly  to  the  owner  than  if  the  reverse  were  true. 

A  large  structural-engineering  office — one  employing  a  large 
force  of  draftsmen  and  designers,  and  carrying  on  work  simultane- 
ously on  several  large  buildings — must  of  necessity  have  a  good  set 
of  office  standards  for  the  guidance  of  the  men  and  as  an  aid  to  the 
chief  draftsman  or  engineer  in  obtaining  uniform  practice  on  all 
jobs  of  the  same  type,  without  necessitating  his  spending  the 
greater  part  of  his  time  giving  instructions  and  personal  supervision 
to  each  and  every  man  or  squad. 

The  office  standards  for  concrete  building  design  should  include 
tables  and  diagrams  for  the  design  of  reinforced-concrete  slabs  and 

M  \ 
beams   (such  as  values  of  K  =  TJZ  )  f°r  various  combinations  of 

unit  stresses;  areas  and  weights  of  steel  bars;  data  on  web  rein- 
forcement of  beams;  reinforcement  of  spandrel  girders;  diagrams 
and  tables  for  the  design  and  detail  of  reinforced-concrete  columns 
and  footings  and  for  steel  columns  incased  in  concrete;  tables  and 
details  showing  amount  and  method  of  reinforcing  concrete  stairs, 
and  standard  sheets  showing  the  arrangement  of  lettering,  dimen- 
sions, details,  etc.,  on  the  floor  plans.  For  steel  building  design  the 
standards  may  include  properties  of  various  types  of  columns ;  con- 
nection details;  bracket  details;  cast-iron  bases;  typical  details  of 
spandrel  beams,  crane  girders,  steel  stairs,  steel  stacks,  tank  floors, 
towers,  etc. 

In  order  that  original  and  special  details  developed — which  would 
not  ordinarily  be  indexed  in  the  general  job  file  or  included  in  the 
standards — may  be  readily  found,  a  card  index  of  various  details 
of  completed  designs  in  the  office  files,  which  are  likely  to  be  used 
on  other  work  or  referred  to  at  various  times,  should  be  maintained. 
With  such  a  file  a  new  man  in  the  organization  can  at  once  acquaint 
himself  with  methods  of  detailing  certain  portions  of  a  standard  or 


158  The  Engineer  in  Field  and  Office 

special  building  without  a  lengthy  explanation  on  the  part  of  the 
chief  draftsman,  thus  saving  much  valuable  time  and  increasing 
materially  the  speed  with  which  the  plans  can  be  completed. 

Filing  Catalogs  and  Pocket  Maps 

Some  of  the  material  to  be  filed  in  an  engineering  library, 
particularly  trade  catalogs  and  folded  pocket  maps,  is  so  diversified 
in  size  and  shape  that  it  is  hard  to  handle.  Thus,  while  it  has 
come  to  be  generally  conceded  that  trade  catalogs  ought  to  be  unified 
as  to  dimensions,  and  while  this  would  be  of  advantage  not  only  to 
the  possible  purchaser  but  also  to  the  manufacturer,  the  catalogs 
continue  to  vary  from  the  flimsy  leaflet  to  the  substantially  bound 
volume.  Yet,  as  the  engineer  uses  them  in  making  estimates  of  cost, 
in  selecting  equipment,  and  in  other  ways,  he  must  have  them  readily 
available  and  well  indexed. 

The  general  indexing  schedule  in  use  in  one  library  is  a  form  of 
the  decimal  system,  by  which  the  books  and  data  are  assembled  under 
various  classifications  according  to  subject  matter.  This  modified 
Dewey  system  was  found  to  be  too  detailed  for  application  to  the 
trade  catalogs,  and  it  was  necessary  to  simplify  it;  that  is,  K  6, 
Water  Works  Distribution  System,  including  in  its  subdivisions  the 
subjects  of  pipes,  valves,  distributing  reservoirs,  conduits,  meters, 
etc.,  became  in  the  simplified  schedule,  K  6,  Water  Works  Pipes  and 
Valves;  while  K  6.5,  Meters,  became  more  comprehensive  and 
included  Measuring  Devices  for  Water. 

Within  each  classification  it  was  decided  to  maintain  an  alpha- 
betical sequence  of  the  catalogs  according  to  the  names  of  the  firms 
issuing  them.  To  do  this  an  exceedingly  flexible  filing  device  was 
necessary,  since  it  was  planned  to  place  the  material  without  regard 
to  size  and  shape  and  without  segregating  the  bound  volumes.  Pam- 
phlet boxes  would  have  meant  considerable  waste  space,  and  vertical 
files  either  the  segregation  of  the  bound  volumes  or  an  unwarranted 
expenditure  for  filing  units.  Heavy  manila  envelopes  were  also 
considered  for  the  filing  of  the  leaflets  and  pamphlets,  but  were 
found  undesirable  both  because  they  were  incommodious,  and  be- 
cause when  the  envelopes  were  stacked  the  exposed  ends  offered  on 
surface  for  indexing. 

It  was  decided  to  use  a  pasteboard  receptacle  open  at  the  top, 
containing  cardboard  folders  with  tabs,  such  as  are  used  for  filing 
correspondence.  The  containers  come  in  two  widths,  1  in.  and  li 
in.,  and  are  12  in.  long — just  the  depth  of  the  open  shelves  upon 
which  the  catalogs  were  to  be  stacked.  The  exposed  end  of  the 


Filing  Data  159 

unifile  is  curved  and  is  covered  with  heavy  brown  paper.  Upon  this 
a  sticker,  bearing  the  classification  number,  was  placed.  Except  in 
those  instances  where  a  whole  container  was  devoted  to  the  catalogs 
of  a  single  firm,  the  indicating  of  the  contents  upon  the  end  was 
avoided,  so  that  as  new  material  was  added  the  cardboard  folders 
could  be  shifted.  On  the  tab  at  the  top  of  each  folder,  however,  the 
name  of  the  manufacturer  and  the  classification  number  were  placed, 
while  on  the  bound  volumes  and  the  thicker  of  the  pamphlets  strips 
were  pasted  with  the  firm  name. 

In  connection  with  this  file  a  card  index  of  the  names  of  the 
manufacturers  was  maintained,  with  the  classification  number,  or 
numbers,  under  which  the  catalogs  of  each  firm  were  to  be  found. 
It  has  proved  extremely  useful  to  include  also  in  this  index  the  trade 
names  of  materials,  since  these  so  often  differ  from  the  name  of  the 
manufacturer  or  of  the  firm  issuing  the  catalog.  As  the  catalogs  are 
assembled  according  to  subject  matter,  a  subject  index  has  not  been 
found  necessary,  but  reference  to  an  advertising  index  is  made  when 
doubt  arises  as  to  the  manufacturer  of  some  special  material.  This 
method  has  been  tried  out  for  five  years,  in  the  filing  of  16  shelves 
of  catalogs,  and  found  satisfactory. 

From  the  very  fact  that  they  are  designed  to  be  tucked  away,  the 
pocket  maps  are  likely  to  be  tossed  into  a  desk  drawer  or  placed  in 
a  pigeonhole  and  forgotten.  It  is  wise,  therefore,  to  have  a  file  of 
them  in  some  conspicuous  place  where  they  will  be  readily  accessible 
and  will  not  be  overlooked.  Like  the  trade  catalogs  the  pocket  maps 
vary  in  size  and  shape,  for  while  some  seem  designed  for  the  coat  or 
outer  pockets,  very  many  are  long  and  flexible  and  of  a  form  suit 
able  for  the  vest  or  trousers  pockets.  A  simple  device  for  main- 
taining a  neat  and  uniform  file  of  such  maps  is  the  heavy  manila 
envelope  of  standard  size  (4i  in.  by  10i  in.)  with  its  flap  removed 
and  a  cloth  tape  tab  H  in.  in  length  pasted  on  the  closed  long  edge. 
On  this  tab  the  brief  title  of  the  map  is  written.  The  envelopes  are 
filed  on  end  in  alphabetical  sequence  of  the  titles  of  the  maps.  The 
tabs  are  bent  to  one  side  and  as  they  have  been  pasted  at  varying 
intervals  on  the  long  side  of  the  envelopes  it  seldom  happens  that 
they  overlap.  If  it  should  chance  that  a  map  is  too  long  for  an 
envelope,  the  latter  may  be  slit  at  the  top  end.  This  file  is  kept  in 
a  glass-front  case  and  stacked  by  means  of  tin  rack  ends.  Rack  ends 
placed  behind  the  envelopes  will  keep  them  from  slipping  back  on 
the  shelf.  In  the  general  card  catalog  of  material  in  the  library,  the 
maps  are  listed  under  the  subject  "Maps"  and  also  under  the  in- 
dividual titles. 


160 


The  Engineer  in  Field  and  Office 


Value  of  Carefully  Kept  Stadia  Notes 
It  is  especially  important  that  some  definite  form  of  note-keeping 
be  followed  in  making  stadia  surveys,  even  if  they  are  to  be  platted 
by  the  one  who  makes  the  survey.  There  are  so  many  classes  of 
information  to  be  recorded,  that  if  the  work  is  not  done  systemati- 
cally, the  value  of  the  data  recorded  is  lost  through  the  impossibility 
of  transferring  the  information  contained  in  the  notes  to  a  scale 


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map.  This  form  must,  of  necessity,  be  adapted  to  the  work  to 
be  done,  and  should,  so  far  as  practicable,  conform  to  established 
forms  of  note-keeping.  A  form  used  in  making  drainage  recon- 
naissance surveys  is  illustrated  by  the  accompanying  sample  of  notes 
which  were  recently  taken  in  the  field. 

Turning  points  and  instrument  points  are  numbered  successively 
— arabic  figures  being  used  for  turning  points,  as  they  are  usually 
placed  on  the  stake  by  an  untrained  assistant,  and  Roman  numerals 
for  the  instrument  points.  The  turning  points  are  available  for 
later  cross-line  surveys.  All  instrument  heights  and  heights  of  turn- 
ing points  are  calculated  in  the  field  as  well  as  the  stadia  distance.  A 
mental  calculation  is  made  by  adding  one-half  the  observed  distance 
to  the  lower  stadia  reading  as  a  check  on  the  level  reading  on  the 
central  cross-head.  This  also  serves  as  a  check  on  the  observed 
distance.  "- 


Filing  Data 161 

In  line  surveys  the  distance  from  starting  point  to  each  instru- 
ment point  and  turning  point  is  computed  and  recorded  in  the  dis- 
tance column,  this  computation  being  done  at  night,  or  after  return 
to  the  office.  After  being  checked  by  adding  the  observed  distance 
from  starting  point,  the  total  distances  are  set  down  in  ink  and  are 
of  assistance  in  platting  the  survey. 

Location  of  Water  Mains,  Connections  and  Valves 
Kept  on  Card  File 

Any  card  system  of  keeping  records  which  has  proven  its  value 
by  twenty  years  and  more  of  continual  use,  without  radical  change, 
is  worthy  of  notice.  In  this  class  falls  the  card  system  for  re- 
cording the  location  of  water  mains,  valves,  connections,  fire  hy- 
drants and  other  special  fixtures,  which  is  in  use  by  the  Water 
Department  of  the  City  of  St.  Louis.  This  system  comprises  the 
use  of  specially  printed  4x6  cards  kept  in  drawers  and  referred  to 
ordinarily  only  by  members  of  the  office  force  of  the  distribution 
system.  The  accompanying  illustration  gives  a  very  clear  indication 
of  the  nature  of  the  card  and  the  information  kept  on  it.  Each 
size  of  pipe  and  each  particular  fitting  has  a  special  symbol,  and  the 
situations  of  all  valves  are  marked,  showing  their  position  with 
reference  to  the  curb  or  building  line. 

The  street  running  from  bottom  to  top  is  an  east  and  west  street, 
and  from  left  to  right,  a  north  and  south  street.  The  east  and  west 
streets  follow  each  other  alphabetically  in  the  drawers;  that  is  to 
say,  Atlantic  Ave.  would  come  before  West  Ave.,  and  all  intersec- 
tions with  north  and  south  streets  are  represented  by  succeeding 
cards  which  start  from  the  most  easterly  intersection  of  the  east  and 
west  street  with  a  north  and  south  street.  Therefore,  to  locate  any 
intersection  it  is  necessary  only  to  know  which  of  the  streets  is  an 
east  and  west  street. 

Each  card  is  inclosed  in  an  envelope  of  transparent  paper,  which 
keeps  it  from  being  soiled  by  the  rather  excessive  handling  to  which 
cards  of  this  sort  are  subjected.  It  is  only  possible  to  take  the  cards 
from  the  drawer  by  unlocking  a  special  keeper-rod,  the  kkey  to  which 
is  guarded  carefully  and  is  never  allowed  to  leave  the  possession  of 
the  chief  draftsman  of  the  water  department. 


162 


The  Engineer  in  Field  and  Office 


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Filing  Data  163 

Filing  Records  in  a  City  Engineer's  Office 

The  filing  of  the  city's  engineering  records  in  Los  Angeles  is 
fully  explained  by  George  H.  Tilton,  Jr.,  of  the  City  Engineer's 
Office.  The  classification  is  as  follows: 

1.  Records  showing  location  are  termed  maps. 

2.  Records  showing  profiles  are  termed  profiles. 

3.  Records  showing  detail  are  termed  plans. 

4.  Fieldbooks,  deeds,  etc.,  are  self-explanatory. 

Mr.  Tilton  says:  "The  conglomeration  of  sizes  is  sorted  into 
lengths  and  a  series  of  numbers  is  allotted  to  each  length  in 
each  classification,  as  follows:" 

1  to  249  Roll  maps  12  in.  wide  and  under. 
250  to  1.999  Roll  maps  12  to  18  in.  wide. 

2,000  to  3,999  Roll  maps  18  to  24  in.  wide. 

4,000  to  5,499  Roll  maps  24  to  36  in.  wide. 

5,500  to  5,999  Roll  maps  over  36  in.  wide. 

6,000  to  9,999  Flat  maps  of  a  uniform  size. 
10,000  to  10.249  Roll  profiles  12  in.  wide  and  under. 
10,250  to  10,999  Roll  profiles  to  18   in.   wide. 
11,000  to  14,999  Roll  profiles  18  to  24  in.    wide. 
15,000  to  19,999  Flat  profiles  of  a  uniform  size. 
20,000  to  20,999  Roll  plans  12  in.   wide   and   under. 
21,000  to  21,999  Roll  plans  18   to   30   in.    wide. 
22,000  to  24,999  Roll  plans  30  in.  wide  and  over. 
One  up  for  fieldbooks,  deedbooks,  etc. 

As  soon  as  one  of  these  series  of  numbers  is  exhautsed  the 
alphabetical  prefix  is  assigned  and  the  series  re-run. 

The  actual  indexing  and  numbering  is  now  ready  to  be  done 
rapidly  and  accurately.  Each  record  is  numbered  with  a  stamp 
so  that  all  numbering  is  of  uniform  size  and  in  the  same  location 
on  the  record.  Each  classification  is  listed  in  a  "list  book"  and 
indexed  both  in  the  "division  index"  and  "alphabetical  index"  so 
that  it  can  be  found  either  by  name  or  location,  one  of  which  it  is 
necessary  to  know.  In  the  division  index  the  records  are  arranged 
according  to  year  made. 

Sixteen  years  ago,  when  this  system  was  inaugurated,  the  area 
of  the  city  was  43.26  sq.mi.;  today  it  is  337.92  sq.mi.  This 
continued  expansion  has  not  impaired  or  confused  the  early  records 
in  any  way,  in  fact  an  early  record  is  found  as  quickly  as  a  late 
one.  To  keep  this  system  up  to  date  and  the  records  in  place  the 
entries  services  of  one  man  have  been  found  necessary. 

Large  Number  of  Road  Plans  Filed  in  Simple  Rack 

The  accompanying  photograph  shows  the  method  of  filing 
blueprint  road  plans  of  a  large  number  of  townships.  The  scheme 
consists  merely  of  mounting  the  blueprints  of  each  township  between 


164 


The  Engineer  in  Field  and  Office 


two  stick  or  lath  binders  and  hanging  each  pair  of  binders  on  an 
inclined  rack.  The  titles  and  numbers  of  the  roads  are  printed 
in  black  ink  on  one  side  of  the  binder  sticks,  and  just  enough 


Rack  Inclined  to  Show  Titles 

inclination  is  given  the  rack  so  that  the  titles  of  all  the  binders 
are  readable  to  one  standing  in  front.  Not  only  is  convenience 
served,  but  the  cost  of  the  rack  is  negligible. 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


AN  INITIAL  FINE  OF  25  CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  5O  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


CIRCULATION 

LD  21-100m-7," 


YC I 05309 


U.C.  BERKELEY  LIBRARIES 


^  - 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


